UNKILLABLE (5e Template)

UNKILLABLE

Have you ever wondered what would an invincible creature be like? To a point where even gods would have an incredibly hard time beating it? I bring thee the ultimate tank, for it shall not perish by any means sort a Wish spell. This template creates an unkillable creature that will shake off all damage and restraints without noticeable effort.

To make it easier to understand, I will divide the template in three parts, each explaining a specific part of this so-called invincibility (Indestructibility, Freedom and Immortality), as well as some additional features that will make it even stupider.

A list of ideas for this template implementation can also be found at the end of the article, in the Ideas section.

Prerequisite

Any creature. A reason for their invulnerability should be provided. Having an invincible creature that simply is maynot be fun and feel like cheating, but giving it an actual purpose and reason to be can be enough to make it a memorable npc that will forever live in the hearts of your players.

Design note

This is NOT intended to be used as a whole, but in parts. For example, if you wanted to create a creature which can't die to damage due to an ancient curse or an ancient spatial primordial who escapes all prisons, you could take only the part related to that, leaving the other features out.
This template would be utterly game-breaking if applied to a player character. If you want to create a PC with this idea in mind, I encourage you to take a look at this build instead: Unkillable (5e Optimized Character Build).

Indestructibility

Understood as the state of complete immunity to damage and other damaging effects. This features revolve around resisting all damage so that nothing can directly take you down. This also avoids most instant death effects, but not death like effects such as petrified.

Statistics

Hit Points Over 101 hp.

It doesn't matter how, but this creature needs to be able to survive a Power Word Kill. This also provides a nice margin for other parts of this template to work with.

Damage Immunities All damage.

Not a surprise, I'm sure.

Condition Immunities exhaustion.

We'll touch the rest later, but for now we will protect ourselves from death by exhaustion.

Traits

Universal Absorption Whenever the creature is subjected to damage, it takes no damage and instead regains a number of hit points equal to the damage dealt.

Why is this necessary, you may ask. Some features and effects allow you to treat immunity as resistance, or in the worst case, outright ignore it. With this trait, all that damage will be automatically healed.

Immunity to max HP reduction

Most of the time this effect is linked to a damaging effect (see Harm for example), and though the creature is technically immune to the damage, we already know that some effects are still capable of dealing damage.

Turn Immunity (Undead only) The creature is immune to effects that turn undead.

What can I say, we don't want any high level cleric/paladin completely disintegrating our guy, now do we?

Optional traits

Rejuvenation If it is destroyed, this creature gains a new body in 1d10 days, regaining all its hit points and becoming active again. The new body appears in the closest empty to the place where it died.

Just in case. You can change the rejuvenation period from 1d10 days to instantly, but it is not really needed.

Alternatively:

Regeneration. This creature heals 1 hit point per hit die at the start of its turn. If reduced to 0 hit points it will fall unconscious and will have to heal all damage taken to 1 hit point and then regain consciousness again in 1d6 rounds. If destroyed outright keep a tally of total damage applied, The creature must heal this total at a rate of 1 hit point per hour until at full health (signifying full body regeneration) before regaining consciousness.

You can increase the hp regen for an easier recovery.

Freedom

This section focuses on avoiding all restraints, be it physical such as chains or mental such as Suggestion.

Statistics

Speed Decent flight (hover), burrowing and swimming speeds.

This section focuses on movility, so this should be a given.

Condition Immunities All conditions.

Having infinite Legendary resistances as we will see soon should get rid of this, but there is no harm in being cautious.

Traits

Legendary Resistance If the creature fails a saving throw, it can choose to succeed instead.

No, there is no limit to how many times it can use this.

Legendary Ability If the creature fails an ability check, it can choose to succeed instead.

Some spells or effects such as illusions, grappling and Telekinesis ask for an ability check.

Free Walker The creature's movement is unaffected by difficult terrain, and spells and other magical or non-magical effects can not reduce the target's speed.

This is actually pretty important because it nullifies Sentinel.

Innate Spellcasting (Psionics) The creature's innate spellcasting ability is intelligence (spell save DC 8+proficiency bonus+intelligence mod). It can innately cast the following spells, requiring no components:

At will: Teleport, Dimension Gate, Gate, Counterspell (9th level), Dispel Magic (9th level).

This spells allow the creature to escape any physical, magic and/or magic cage as long as a different effect does not limit the usage of them such as Antimagic Field or Hallow. To solve this problem, a brand new trait can be created or the Magic Immunity trait can be added. Also, intelligence can be switched to any other stat.

Teleport, Dimension Gate and Gate are used to escape while Counterspell and Dispel Magic let the creature destroy most restrictions that may impede the use of those spells.

Optional traits

Senses truesight unlimited, Passive Perception 100.

truesight should be helpful, and paired with a high enough passive Perception nothing will be able to avoid your gaze. As a sidenote, Legendary Ability already provides the creature with functionally infinite passive Perception.

Immortality

This section focuses on natural death causes such as old age or illnesses.

Traits

Disease Immunity The creature is immune to disease.

Ageless. This creatures does not age nor suffer the effects of old age and can not be magically aged.

Optional traits

Rejuvenation

General optional traits

Magic Immunity Unless it wishes to be affected, the creature is immune to spells. It has advantage on saving throws against all other spells and magical effects.

Not Limited Magic Immunity, straight up TOTAL magic immunity. This actually gets rid of things such as Antimagic Field and Wish.

Innate Spellcasting (Psionics) The creature's innate spellcasting ability is intelligence (spell save DC 8+proficiency bonus+intelligence mod). It can innately cast the following spells, requiring no components:

At will: Misty Step, Plane Shift, Demiplane, Freedom of Movement, some offensive spell (to heal yourself among other things), Regeneration, True Resurrection.

All this spells expand the creature's movility or give it a way to heal itself or even damage its enemies.

Summary

An invincible creature can be made invincible with the least changes to it's statblock by adding the following traits. This summary is a great example of what you probably shouldn't be doing with this template. The resulting creature should be handled carefully.

Statistics

Hit Points Over 101 hp.

Speed Decent flight (hover), burrowing and swimming speeds.

Damage Immunities All damage.

Condition Immunities All conditions, max hp reduction, disease.