Guilty Crown/WMG

Haruka is keeping the last of the 3 void genomes.

And she gives it to Shu after he calls her out because of her actions.

• Confirmed. Haruka DOES have the 3rd Void Genome, though she didn't want to give it to Shu because a second use of the Genome would be most likely fatal for him. He gets it anyway though.

Shu's void will be a void that can copy other voids.

The reasons I think this are because of the way he changes himself to get along with other people since a void is pretty much personality given form,aka changing his opinions when with different people like when he was speaking with Yahiro and Souta respectively he both agreed and disagreed with the void ranking system, and the fact that the Genomic Resonance Gauge cannot discern his void's power, perhaps implying that the value is inconsistent.

• It appears to be confirmed, though the real form of his void takes is the Tron Lines arm from the opening.
  • Let me correct myself. Shu's Void TAKES other people's Voids, and lets him use them when he wants. It's basically a portable Pocket Dimension for Void storage purposes. The thing is he also takes other things with the Voids...like the Apocalypse Virus.

The hand with Tron Lines in the opening...

Belongs to the main character of the Lost Christmas video game. His story will be explained in the coming episodes and it will be his hand that replace's Shu's.

• Jossed: The arm is Shu's Void given physical form.

Gai's recent actions are going to become one massive Nice Job Fixing It, Villain.

The ending of episode eighteen and the preview for nineteen imply that the recent experiences that Shu has been through are what will give him the strength to save the day.

Inori will sacrifice herself to stop the Apocalypse virus.

It began with Mana; Inori will end it. Wathever cure is used will probably kill her. She may be doing this for Shu as she truly does care about him. This could also mean a Bittersweet Ending.

• It appears to be confirmed. Although Inori may come back in the second season depending on artistic direction.

Mana is still in love with Shu.

Notice how despite being at the same place and time Gai was during the Lost Christmas outbreak, Shu was completely unaffected by the virus before receiving the Void Genome. I think she still wants Shu despite clearly having been pissed off about his "rejection" way back when.

• Confirmed, she even tries to rape him through Inori in episode 18.
  • Which raises the question as to how she'll react when GHQ attempts to pull an Adam and Eve Plot with her and not Shu again.

There will be a Theme Music Power-Up in the final episode, and it will be My Dearest.

• I second this motion.

Gai will take over leading Shu's classmates.

And he will be even worse than Shu was post-Despair Event Horizon, leading to a collective My God, What Have I Done? for all those that helped to usurp Shu.

• Partially confirmed. People were complaining that Shu used them as tools. Gai showed what "using as tools" really means.

Shu will try pull a Heroic Sacrifice before the end of the series.

• Whether or not he succeeds is another matter. Still he does seem to be remorseful over being so iron-fisted; maybe he'll think sacrificing himself is how he can atone?
  • You're right in a way. You see, Heroic Sacrifice is the very nature of Shu's Void. It allows him to, in Gai's own words, take on parts of others so that he can shoulder other people's burdens. This allows him to do everything from copy other people's Voids to cure someone of the Apocalypse Virus by absorbing the cancer into himself. DAMN!

Shu will gain the third Void Genome.

And he will save his friends that survived the aftermath of/were captured at the end of episode 17 (after a bunch of GHQ Endlaves showed up.)

• His hand with Tron Lines in the second op may be considered as a confirmation

Confirmed. Every. Single. Word. Every single word said in this WMG entry has been confirmed. Woah.

Everyone will rejoin Shu after seeing his void.

• We know that someone's void represents who they are as a person, and despite his actions, it's safe to say that Shu really does care about everyone. It'd make sense for his void to be something related to saving or protecting them.
  • I just want this to be the case because I feel so bad for Shu! He's essentially the show's resident Woobie!
  • Or they will unite under Gai's reign and confront Shu.
• It appears to be Confirmed. After seeing the effects of his Void, the onlookers are suitably shocked.

Gai will find a way to take the Void genome from Shu

• Confirmed

Mana will come back through Inori

• As of Episode 16, it appears that flashes of Shu's unstable sister Mana are manifesting somehow through Inori, complete with Slasher Smile and what might be another Brother-Sister Incest tease. Even Shu looked freaked out at one point.
  • Apparently Inori actively resists it. For now.

Gai is going to return

• Can't really explain it, but I am just getting this feeling. 
• Ep.15, while Shibungi is playing chess with Segai, he says he'll see 'him' if he wins. Could be Gai.
• Confirmed in Ep.16. Though how much they screwed the checksum while assembling him back is yet to be seen It is really screwed up.
  • I Knew It!!!!
  • Haruka said that "Shu may never forgive me for this. So there's a good chance that Gai really did come back wrong.
    • Turned out he came back right. Too right.

Guilty Crown will have a tragic ending

• Just look at the new opening, in episode 13.
  • Have you seen where it's going as of episode 15? Shuu is now officially R2-Lelouch. "Kindness is pointless. We need to sort the good from the trash!" sounds like something Lelouch could say.
• More like something epic, Code Geass style.

Gai is suffering from the Apocalypse Virus too but hiding it very well

• So in Episode 9, Yahiro's brother Jun reveals that he could see Yahiro's Void and possibly others. Gai has been revealed to be able to see them as well with no explanation offered. Gai may therefore have an earlier less degenerative state of the disease that he keeps well hidden to say the least, thus conferring upon him said ability.
  • Prehaps the blood transfusions he recieves from Inori are what allow him to keep his condition under control
  • Possibly proven correct by Episode 10 due to the fact that the "genetic resonance" broadcast only seems to affect certain segments of the population with a sudden outbreak of the Virus, including, interestingly enough, Gai.
  • Confirmed.

The Apocalypse Virus was released on purpose

• Theory is essentially just that--the Apocalypse Virus which brought Japan and the world to its current dismal state was engineered as a bioweapon for the purpose of destabilizing the world and giving control to whoever is behind the GHQ forces. This is just a hunch, although the bizarre genetic nature of the disease's effects hints at a laboratory origin at least.
  • Jossed. The Apocalypse Virus came from a meteorite crash in Japan.
    • Well obviously the GHQ is being controlled by Extraterrestrials who caused the meteorite to crash as part of their plan.
    • And Second Impact was caused by a meteor. Yeah, right.
  • I Knew It!. In Episode 10 Keido declares "Let us finish what we started--what we lost that Christmas" in reference to the artificial activation of the meteorite..
  • Actually, in Episode 12, it is revealed that Ouma Mana (Shu's dead sister) spread it because Shu wouldn't marry her and pushed her away. So, kinda true, I think...

Inori is modeled after a girl from Gai's past, possibly a Dead Little Sister

• This has been hinted around at below, but I'm going to break down my prediction. Inori is in some way artificial and modeled after a girl from Gai's past. This comes both from the cryptic reference Gai made in Episode 5 as well as the fact that in the Theme Song there are two Inoris which walk together and become one. I also think it's hinted at from the pendant which Gai is seen clutching in the Theme as well, which probably belonged to the original Inori first. I think that the Apocalyptic Virus was what killed the original Inori, just like what is afflicting Yahiro's little brother. As noted below, her artificiality would explain some of her uncanny abilities and general social detachment, as well as her devotion to Gai. Also in Episode 6, during an Inori Void sequence, there is a brief flash of a much more normal looking girl with straight brown hair similar to Gai's who may in fact, be the original.
  • This has been my thought as well. She's possibly a clone of Gai's sister (since he mentions someone he was close to), and the flashes of memory are the sister's (as there are theories that memories could be encoded in genes), each time Shu extracts a Void, he unleashes more of the memories. Which I'll elaborate in a different WMG.
  • This may be only partially right as later flashbacks seem to hint she may have actually been Shu's sister, though there still may be a connection to Gai.
  • True. More specifically, Inori is modeled after Shu's sister, Mana, who saved Gai the summer before Lost Christmas.

Shu's mother was killed during the Lost Christmas outbreak

• When Shu gets the Void Genome we see a bunch of quick flashbacks. There was a woman that resembled Shu, in some sort of fire and bleeding. I believe that this may be a repressed memory of some sort, and that it will act as either the cause of Shu either taking a level in badass or having some sort of horrible breakdown.
  • Unlikely, as Shu mentions his mother telling him about the outbreak. The woman looks more like Inori, so it's possible she's her mother instead.
• I've been jossed. She's alive and has some connections with GHQ.
• Actually, Haruka is Shu's STE Pmother. Shu's real mother died of Apocalypse Virus during childbirth.

Inori caused or was involved with the Lost Christmas outbreak

• Shu's flashbacks show a young girl who resembles Inori and was infected with the same crystal-like state. However, it could have very well been from Inori (or the Inori look-a-like) since the weapon that Shu extracts is sort of crystallized in appearance as well.
  • Some credence to this theory is the fact that Gai remarks how Inori very closely resembles someone he once knew in episode 5.
    • And that girl is revealed to be Shu's sister (whom Shu had forgotten all about to protect himself from sadness).

Shu will be abducted because of the Void Genome.

When he first used the Guilty Crown the bad guys saw a video feed of it too. My guess is the nations controlling Japan, or the organization itself, will really want to get their hands on it's power, and will need to get to Shu to do so.

• HAHAHA!! I CALLED IT! But he wasn't abducted because of the void genome. Shu's friend spilled that he had connections to Funeral Parlor.

Daryl will have a semi-Heel Face Turn.

• Being the asshole Blood Knight he is (They don't call him Kill'Em All Daryl for nothing) he'll do it purely for the hell of it, or at least have a substantial amount of Break the Haughty Humiliation Conga heaped onto his life.
• seems like he feels something for Tsugumi.
  • Aaand he disobeyed the orders beacuse of it, so may be confirmed

The lock of pink hair on Shu's head is a reference to Inori.

• Shu's hair is brown, but he has a lock of pink hair near the front. This could be anything from simple fan devotion to a crucial point in the backstory. We'll find out as the series progresses, probably. 
  • I dunno. It doesn't really look pink. It's a really pale tan as far as I can tell.
    • Yes, you are partly right. In the anime, it's almost always portrayed as a pale tan rather than outright pink. But, here is some official artwork from the Guilty Crown website that shows him having a pink strand. 
• Well, Shu's dad had the same strand, so it appears he simply inherited it.

Daryl is going to become obsessed with finding Shu and bringing him down.

At the end of episode two, Daryl saw Shu's face as he removed Daryl's void. We all know how unstable and downright Axe Crazy the freaky blond kid is. He's definitely going to want to give Shu a piece of his mind.

• Most likely jossed, having your Void removed is so big shock that you forget the event and what happened directly before it.
  • Un-jossed! Daryl might not remember having his Void removed, but he's seen Shu in action with the voids more than once (although the voids hide his face from electronic devices, including Endlave cameras). Daryl goes straight for him every time they see each other in battle. He seemed rather pissed in episode 10 when he couldn't beat Shu.

Shu will become a Messianic Archetype

The power of kings is referred to over and over again as if it were some awful burden--that Shu is willfully taking on a great sin for the sake of everyone else. Also, the OP makes reference to being forced to wear a crown of thorns...

• On the other hand, if we go with the WMG that being used as a Void weapon has negative effects, Shu might be killing his "friends" and finding that out will lead him to being a pragmatic hero (or villain) who is willing to sacrifice anyone to achieve his goals.
• The power of his Void essentially makes him into this. He takes in EVERYTHING with his Void...including the taint of the Apocalypse Virus, which appears on his body. However, he arguably lapses into Dark Messiah a bit, as he says he "will dirty his hands as much as it takes for them (his friends)".

The other two Void Genomes also have titles

Like the way the Void Genome that Shu has is called the "Power of Kings", so the other two will have similar "Power of X" where X could be nearly anything. Possibly "Power of Queens" for one of them, for example, if they were going with a royalty motif.

Gai has a Void Genome

How else did he predict that Daryl's Void would produce a Beehive Barrier-producing gun that, as a side effect, produces a visual effect not unlike a Kaleidoscope? It also makes sense if one "power" was the ability of "Insight" and "Extracting Voids (weapons) from people" - together they're a potent combination which would befit Gai (Fighting Skills - Shu's Void Genome and Tactical Mind - Gai's talents) and be possibly another reason he intended to have Shu's Void Genome.

• This may or may not be true. It's been confirmed that Gai can see people's Voids, but we don't know why.
• Jossed in episode 10, he suffers from the Apocolypse Virus.
  • Un-Jossed, who could have thought that taking away the Void Genome would be as simple as cutting the owner's arm?
    • Though, on second thought, it may be subverted: Gai doesn't use the Void Genome, he uses his own void which draws others' voids. So Shu may as well still have Void Genome.
    • He doesn't. Gai really took Shu's void, and this is seen when he extracts the Void of a scientist by hand to capture Inori. Shu gets the final Void Genome though.

Keeping a Void extracted for too long has a negative effect.

Gai doesn't seem like he'd want Shu to just put a Void back without good reason.

• Probably something like, I don't know, brain damage, probably?
• Confirmed and subverted: keeping the Void away from the user is generally ok for any period of time, but breaking it means dying of the owner

Shu's class will find out about what Yahiro did.

A lot of kids were pretty shocked that Shu was arrested, and those closer to Shu were clearly saddened. A lot of his classmates saw him get carted off after Yahiro pushed him. Somebody had to see that happen and put two and two together. If this is the case, then Yahiro is probably going to face some serious resentment at the hands of his classmates. 

• That is, if he wasn't killed in episode 4.
  • They would've shown something like that.
    • Wat exactly forces them to not drop it as some big thing next episode?
• Jossed. No one cares about that anymore, besides, Yahiro piled up enough other lies

Gai is evil.

Very much hope that he is manipulating Shu, using Inori as a lure.  He will eventually gain/use Void Genome powers and win over GHQ. Then he becomes just like them, then Shu and Inori will probably fight him...

• I think that you do have something there... But I feel like it would wind up being like Code Geass, only from the perspective of those that weren't aware of the details of the Zero Requiem. (I'm not spoiler tagging this because this isn't a Code Geass page, but some major CG spoilers are coming.) Gai wants everyone to consider him evil in order to pull of some sort or massive Batman Gambit involving the population of Japan somehow.
• As of Ep.17, he indeed is evil.

Inori is an artificial human or at least part cyborg.

In episode one, she was shot, fell off a bridge, and abused, yet there are no signs of injuries besides a bandage on her arm. In episode four she invaded a highly guarded prison solo in plain sight without being shot down, jumped above 50 feet into the air over a building, and freefalled down that same height with probably no knowledge of Kenji's gravity gun and expected to live. Episode five reveals that she looks like a certain woman and had no name until Gai gave her one. A plausible theory is that she's a clone of said woman and maybe Gai was involved in breaking her out of somewhere and giving her a chance to live as a person rather than an experiment, thus her lines of "He gave me a world." This would possibly explain her lack of a personality as well.

• To no insult to the voice actress, it could be an explanation for her well-regarded singing: it's all the result of programming and hardware.
  • I always thought that Inori's outfit looked as if it was based off of Vocaloid Miku Append's outfit. If Inori is programmed to sing, then that would make a lot of sense considering the character designer's (redjuice of supercell) connection to VOCALOID.
• Proven true in Episode 12.
• If there was any doubt about the validity of this WMG, then Episode 18 should clear them all away. CONFIRMED.

Extracting Voids grants Shu access to that person's memories.

It appears that each time he uses Inori's void, Shu sees flashes of what may be her past (or another girl's as some theories propose). This could also hold true for the other people he's extraced a Void from, which could play a role down the road for both Shu's sanity, and growth as a character.

Segai isn't evil, but he isn't exactly good, either.

From what has been shown so far, he just seems to be have a rather weird fixation on seeing amazing sights like the Void power, to whether a person like Shu will do what is expected of their nature.

• As of episode twelve, this really looks like the case. Segai even helps out the good guys just because Keido wouldn't let him go any further. He calls it his way of "picking on him." (According to the FUNimation translation at least.)

Theories on future Voids.

Come on. Lets hear 'em.

• Ayase's void is a wheelchair.
  • Or a giant robot.
  • Revealed to be a super exoskeleton for her legs.
• Shu's Void is Crown of Thorns.
  • It's actually the Tron Lines arm from the 2nd opening, which replaces his missing right arm. It lets him absorb other's Voids so that he can use them at will, AND it can take away the Apocalypse Virus...but only if Shu bears it instead. Also, if he dies when he has someone else's Void, they die too.

Shu has Asperger's Syndrome

• He's too socially capable for that, schizoid personality disorder may be a closer call.

The Apocalypse Virus was accidentally created and released during development of the Void Genome.

Note that Shu's arm while drawing a Void is covered in the same crystal that envelops the body of a person with the virus. The Apocalypse Virus is likely an "imperfect" stage of what eventually became the Void Genome, and was accidentally released at some point to devastating effect.

And about the "Apocalypse Virus is from a meteor" Jossing further up the page...who's to say that it's not simply GHQ propaganda?

• I think it's the other way around. I think that the virus came from the meteor, like GHQ said, but while developing the vaccine, they found out how the virus worked (lets just assume that the crystallization happens when the virus screws with people's genes) and managed to refine the process into the Void Genomes. 
• Jossed. The virus was spread and apparently amplified by the original infectee, the first person to touch the meteorite: Mana Ouma. The Void Genome apparently came later.
  • I retract that jossed. It seems that the third Void Genome mentioned belongs to the main character of the Lost Christmas video game. If the game takes place during the earlier stages of Lost Christmas or if Lost Christmas itself didn't last for a very long amount of time, then it's still possible.
    • Gonna have to re-Joss here. Unless there's an unmentioned fourth Void Genome, the third just got used by Shu.

Gai is assembling a human arsenal for Shu

Based on Funeral Parlor's rescue of Kenji Kido, it seems that Gai only wanted him for his Void. In order to guarantee Shu has good Voids around to use for Funeral Parlor at any given time, since having to find a useful Void in the middle of a battle would be annoying. But then it progresses to the point where they're just prisoners of Funeral Parlor to be used as weapons. And Shu doesn't like that.

• Addendum to the above: Gai will imprison them and create a sort of electronic catalog that allows Shu to draw any of the people's Voids, wherever he is and whenever he wants (this is based on the OP).
• Partially Right: In the show's second half YAHIRO sets up a Void ranking system for Shu made up of the students at their school.
• Judging by Ep.16 and everyone's vague remarks, all involved parties are interested in army of void users under Shu's reign, for one reason or another.
  • Also judging by Ep.17 and the preview of Ep.18, Yuu has apparently a literal void storage.

Gai has the Apocalypse Virus

We already know he can see Voids, but in episode 9, when Shu gets to talk to Jun, the latter says "the crystals that stole [his] life" let him see Voids.

• Confirmed in episode 10

The bonds of people is the true power

Since it's what Shuu theorized in Episode 8 after hearing about how the void changes when the heart of the person changes. He figures his power will grow by "Forming bonds" with people. Like social links.

• Your power to extract voids has grown!
  • Heck, he even fused voids in one episode.

Keido is the Big Bad

Keido will pull a We Can Rule Together.

Either with Shu or with Gai. Most likely Shu.

Gai is Big Bad

Ayase is not really handicapped.

She didn't want Shu watching her getting up in the chair on her own. Maybe she doesn't really need it, but uses it to make people underestimate her? Also, her legs look quite healthy. 

• The legs may have an explanation. There are ways to exercise even paralyzed legs.
• Developing WMG further, her leg trauma may be psychosomatic in nature.

There will be a void that can heal the Apocalypse Virus.

Voids can do Newley anything, so log as it's something related to the personality/desires of the person they came from. There are probably a lot of people out there (especially amongst Lost Christmas survivors) that would give anything to put an end to the cause of Japan's woes, so a void that can help do so would only be natural.

• Hare's Void can heal broken things
• Shu's Void can remove the Apocalypse Virus from the bodies of others...but the Virus will appear on his body instead.

GHQ and Funeral Parlor will join forces in the second half of the show.

From episode 10, the two sides might have to put aside their differences to take on an even greater threat.

• Doesn't look like that's gonna be the case any time soon. Also, it would be too cliché to be likely.
• At this point, there's basically no Funeral Parlor anymore
• Partially confirmed: Shibungi, Kido and Gai are working for the GHQ, Argo, Ayase, Oogumo and Tsugumi are apparently on their own now, as is Shu and Inori. All the others are apparently dead.

Hare's void will be used to heal Ayase.

• Jossed: Hare's dead, so alas, not by her

Theories on why Keido intentionally released the virus, and what it has to do with the red-haired girl.

Don't be shy. 

• Keido only released the virus. Ouma Mana spread it because Shu didn't want to marry her.

The true Big Bad is Scarface.

• Jossed, Shu used Yahiro's Void to cut his life in episode 19. Then again, Gai came back, so it's honestly still possible.

Mana proposing to Shu wasn't just her being insane.

The virus itself needed/wanted Suu for some reason. Mana mentioned genes or something along those lines when she finally popped the question to young Shu when they were in the church. Maybe Shu has compatible or special genes like that; something that the virus needs in order to advance. if this is the case, it could lead to more complications for Shu later in the series.

There will be another Plot Tailored to the Party episode before the end of the series.

And it will involve people using their own Voids.

• seems like Ep.17 is going to be like this, judging by the preview
  • Confirmed for Ep.17, though I suspect there will be yet another such episode.

Shu will end up leading Funeral Parlor.

Or at least be fairly high up. He's been becoming quite the badass, and the second opening seems to show him in a longcoat very similar to Gai's...

Inori will die.

If this is in fact a Spoiler Opening, the second OP shows her surrounded by the same red DNA ring that Jun had when Shu used Yahiro's Void to end his life.

• That same red ring also appeared when Shu first drew Inori's Void and when Keido tried to Mary her in order to awaken Mana. I don't think that it represents death, but something important bout life and life's connection to Voids. 
• Judging by all the semiotics and symbolism stuff in Op2, she may be the only one of the principal cast who's alive in the end.

Shu is going to be severely injured in episode 15.

Go to the official website and you'll be able to see the preview. At the very end, we see someone with Shu's haircut (I won't say Shu because we can't see his face very well) covered in what looks like bullet holes. 

• Confirmed. Turned out to be burn scars. He's healed by Hare, at the price of her own life.

Shu will use his own Void at some point.

Or have it used. Alone and with no one to help, Shu does the desperate thing...and yanks out some kind of Void repository, which lets him use all the Voids he's ever used before.

• Although having a Void Genome is essentially saying "you have no void," if done well, this could be very cool. At the last moment, his void would be the representation of all of his character development--his hardship hainv g formed his Void into something incredible and powerful. However, if they do this poorly, it could feel like Deus Ex Machina meets New Powers As The Plot Demamds, with Suu in desperate need of an omnipotent Void. 
• That, or maybe he can revive anyone he used the Voids from. 
• Since it's been heavily implied that the Void Genome nullifies the "king" in questions' Void, the fact that in episode seventeen Gai comes back evil and promptly chops Shu's arm off and steals the Void Genome, this might happen in episode 18.
• Confirmed. Shu finally uses his own Void after gaining the third Void Genome in episode 19. It's full effects have been described as the ability to absorb other people's Voids, cancerigenous cells, and the Apocalypse Virus, the latter of which appears on his own body. Also, according to Shu, if he dies while he has other people's Voids inside of him (because it takes them and KEEPS them within him), they die too.

Hare will die.

Face it. All of the death flags have been tripped, and the fact that Hare is basically an Expy of Shirley does not help at all.

• Proven. Its result is a Tear Jerker, Nightmare Fuel for everyone (especially Inori), Took a Level in Jerkass, Heroic BSOD, and a stare that would do Light proud. 

The current arc will end with a heroic Do Not Adjust Your Set.

The students at Shu's high school will somehow manage to show the world that there are survivors within the walls that are uninflected, vaccinated, and healthy, and, subsequently, how GHQ flat-out lied to the world in order to further their own goals - whatever they may be.

• Jossed: Gai and GHQ took them under their control.

President Keido is a puppet

Bushy-Eyebrows knocked him off in Episode 12 and took over.

• Or maybe there's no President Keido at all.

Segai is Shu's father

He's kinda too interested in him.

• Jossed. Segai's obsession with Shu was a subsequent result of his obsession with Voids, although he does seem...happiest...when Shu is the one using the Void Genome. He's not nearly as ecstatic when Yuu or Gai do so. He also doesn't protest at all to Shu gaining the final Void Genome, whereas he pulled out all the stops to keep Ayase from using it. And also, it's been 100% stated that Shu's father is dead: he was killed by Keido. And the previews for episode twenty show that it's going to be another flash back episode, and we've already been shown Shu's dad in the previews. He looks nothing like Segai and seems to be a genuinely benevolent scientist.

Segai is a descendant of Izaya

And is equally bored troll.

Guilty Crown takes place before Gundam 00.

Granted, it's a long time before, but follow me on this one. The Apocalypse Virus is human-made, right? Ergo it might just be a prototype for a more powerful, sentient organism. Now go watch the Gundam 00 movie, and tell me the ELS might not just be a sentient, upgraded Apocalypse Virus gone awry. The way they kill anyone who comes into contact with them only serves to prove this theory more correct. And it would be a secondary explanation for the Jupiter expedition that took place 80 years prior to Gundam 00. They wanted to get the Apocalypse Virus as far from Earth as they could, and they needed materials from Jupiter anyway, so they simply dropped the Virus on Jupiter and expected never to see it again.

Shu will murder Souta and the other F-Ranked users.

• For Souta it'll mostly be out of revenge, while for the others it'll be to "Seperate the trash form the good."

In the end Shu will change his appearance, go back to the past, and appear on that coast.

• Jossed. That most definitely wasn't a time-traveling Shu. It was a then-nameless boy escaping from a facility where children had horrific experiments involving the Apocalypse Virus performed on them.

Yahiro is working for the GHQ.

For being outside the quarantine zone, the GHQ seems to be very well informed about what's going on inside of it, specifically Tennouzu High School. In fact, some of them seem to regard what's going on as exactly according to plan. The direction things have gone in can arguably be traced back one individual and it would make a lot of sense if this person was acting on behalf of the GHQ to move things along a certain way and passing information back to them. Yahiro. Set up the void ranking system, help set Shu up to be the school president, is among the leadership of the new school regime and seems to be heavily involved in all matters, and keeps ensuring that Shu stays on his current path, sometimes even taking command of a situation. 

• Also, it was confirmed earlier in the series that he was an informant working directly under Segai. Who's the say hes still not working for him?

Inori has some part of Mana's personality

For a moment in Ep.16, she said in Mana's voice "Are you sure I'm what you want?" and her yandere-mode are somehow reminiscent

• Essentially confirmed. And Inori is scared of it.

The ranking system only applies when people are using their own Voids

And Shu can always draw out their full potential.

• or maybe the scanner shows numbers at random.

Everything that's happened so far has been a massive Gambit Roulette initiated by Shu's father.

Just listen to what Haruka said in episode 16, how no one has been phased by how Shu is gathering an army of kids with strong Voids, and how the blonde Void Genome-user keeps on saying things along the lines of All According to Plan. They keep on mentioning Mana and Shu's father as well. What the ultimate goal of this plan is, I do not know.

Ayase will die.

• May as well say everyone will die, and the world will end, and Shu will create a new world. What? Don't look at me like that.
  • Completely jossed.

The first opening, My Dearest, has been foreshadowing.

Looking at the lyrics for the song, there are a few verses that are matching up with the events that have been going on so far such as Shu getting betrayed by his entire "kingdom" and given a "crown of thorns" (since the students see him as evil). There's one verse in particular that stands out right now:

I will become the light to shine in your path, even the king of this world cannot block me out

When Gai returns and completely breaks Shu in episode 17, he calls himself the true king. What does this mean? Inori's going to have a Big Damn Heroes moment against him!

• There are even lyrics that allude to Shu's Start of Darkness!!

I lost all my chances. The time that you, who had been engulfed by darkness / Seemed to swallow all of your hidden despair

Shu still has the Void Genome

If you pay attention at all the times Gai is extracting voids, you may see the characteristic triangles of his void-drawer gun. So he simply uses his void, not the Void Genome. Which means that either it's lost with Shu's arm, or Shu still has it.

• It's possible Gai's Void, which was pulled out by Yuu earlier in the episode AND has the ability to pull out Voids, fused with his new Void-Arm when he absorbed the Genome from Shu. It looks different and does the same things, but it is 100% genuine Void Pulling.
• Jossed, he just took the third of the three.

The Scanner was a ploy

It was specifically planted with the raiders by Keido to cause chaos amongst the students and, more importantly, Shu.

• Not exactly a WMG, since the guy who helped the raiders was clearly Segai.

Shu's Void doesn't let him use other people's Voids, it let's him copy them.

Where as Gai's merely manifests the person's Void, and thus exposes that person to the danger of Void destruction, Shu's copies any that he's either 1) used before or 2) within a certain distance of. The difference is that, if this copy is destroyed, the person he's copied is in no danger...but Shu is. More or less based on the coloration of the Voids he used during episode 19, them being so similar to his Void's color and not the normal Voids.

• Completely jossed. Shu's Void is essentially an extension of regular Void Extraction. He pulls the Void, and then his Void absorbs it. He can keep multiple Voids (currently unknown how many, but potentially infinite), and use them at will. His arm is basically a pocket dimension where he keeps Voids that he can pull out to use whenever he needs them, and he can simply return them to their owners later. The additional effect of his Void is that it also takes in the Apocalypse Virus infection from those whose Void he extracts. That person is then cleansed of the Virus, but their infection appears on Shu's body instead. And lastly, if Shu dies while he's absorbed other people's Voids, then those people die with too.

Voids are Stands

Superpowered manifestations of a person's soul? Check. Break them and you kill their owner? Check. Brought on by contact with a mineral from space? Check.

There will be no sequels.

• Have you heard of GUILTY CROWN: Princess of Deadpool? Though it's a Spin-Off, so it may very well have a different plotline.
  • Despite being a Spin-Off, it is confirmed that it's also a sequel. This cover image has an older, post-epilogue Shu, looking anguished, in the upper left corner.