Revenant Horror

 is a Slayer Boss in the Zombie Slayer branch. It cannot be damaged with bows, as it heals when it is touched by an arrow, and it is also immune to potion effects.

Spawning
The Revenant Horror spawns as the end boss of a Zombie Slayer Quest after the required amount of Combat XP is earned by killing Zombie-type mobs. When the last required mob is killed, purple particles will appear around the location of its death, and the Revenant Horror will spawn in its place after a short time.

Behavior
The Revenant Horror is a Zombie-type mob which is hostile towards all nearby players. It moves at a relatively fast pace and deals damage with its scythe weapon.

All Revenant Horrors are immune to potion effects, and heal when hit by arrows. They are immune to the item abilities of Aspect of the Dragons and Ice Spray Wand. Additionally, Revenant Horrors are immune to all ability damage as well as damage from Bonemerang.

As with all Slayer bosses, if the Revenant Horror has not dealt damage to a player for some time, it will begin rapidly regenerating health. The regeneration immediately stops when it hits a player again. Additionally, if either it or its target stays in the same block for too long, it performs a slam-dunk attack, knocking the target towards it and dealing. If 3 minutes pass without the boss being defeated, it will despawn, failing the Slayer quest. A timer is shown above its head indicating the remaining time.

through Revenant Horror have all the abilities of the tiers below them.

and
After 40 seconds, it will enter a "Mad" state, in which its behavior is not changed. After another 5 seconds, it will enter an "Enraged" state, in which it moves slightly faster and deals highly increased amounts of damage. This enraged state lasts for 12 seconds.

The boss is much different from the bosses preceding it. It has a different appearance and is named "Atoned Horror" instead of "Revenant Horror". It is also immune to all types of ability damage as well as damage from Bonemerang. It has a rapid natural regeneration effect.

Every second, a circle will appear beneath its target's feet similar to the Gaia Construct, but made of different blocks and larger in size. The center is red and progresses to white. After a short delay, the Atoned Horror will throw a block of TNT to the center of that circle. The TNT explodes on contact with the ground; enemies within the white zone take damage equivalent to 1/3 of their max health, while enemies in the red zone alway die regardless of armor. Upon reaching 1/3 health, the boss enters an enhanced stage, throwing TNT twice as often. The boss remains in this state even if it regenerates health back to above 1/3.

After 30 seconds, it will stop moving and attacking, and a circle of bedrock forms around its feet. A timer appears above its head labeled "Boom:", counting down from 5 seconds. Nearby mobs flee from the Atoned Horror when this happens. Upon reaching 0, the Atoned Horror unleashes a barrage of lightning around it, killing anything within a 7 block radius. This attack bypasses protection from the End Stone Sword. After that, it resumes attacking as before.

Minibosses
The following Minibosses have a chance to spawn when you kill a Zombie while a Revenant Horror slayer quest of or more is ongoing. These Minibosses provide more combat experience and Zombie experience than naturally spawning zombies, therefore speeding up the process to spawning a Revenant Horror. It is also possible that after killing one of these Minibosses, another one could spawn immediately.

Tips
Show/Hide List of Tips
 * Any of the Dragon Armors reforged to Fierce are recommended options if you're looking to take down a Revenant Horror
 * For the Revenant Horror, using a Strong Dragon Armor or better armor set, with a max enchanted Reaper Falchion will help immensely.
 * If it gets enraged, run away until it calms down.
 * If you or the boss stays on the same block space for too long, it will result in you taking True Damage and massive knockback from the boss (+ only).
 * Trapping the Revenant Horror in a lift in the Deep Caverns can make the fight a lot easier. Additionally, spawning the boss in the Diamond Reserve or Obsidian Sanctuary and luring it into lava can hugely reduce the Revenant Horror's mobility and prevent it from landing hits on you, however be aware it can still use Life Drain which can drain your from a distance.
 * For or higher bosses, healing items such as Power Orbs and weapons with  or  are essential.
 * Advanced players may sword-swap from a Giant's Sword or Emerald Blade to a Reaper Falchion or Axe of the Shredded in order to deal extremely high damage per hit. With this technique, even the  boss can be felled in 2 or 3 hits.

Trivia

 * There are leaks for a Tier 6 Revenant Horror and a Tier 7, each being called the Shredder Horror and Revenant Warden. The Shredder has and the Warden has . Those are part of the Slayer v2 Update, which was rumored to be canceled.
 * Because it's immune to arrows, it is also immune to the effects of Voodoo Doll and will not be affected by the damage over time debuff.
 * The Revenant Horror is the first Slayer boss to have a variant. It is also the only boss with an  drop.
 * The TNT from the boss bypasses the protection of the Mithril Coat.