Recover is just your typical healing ability. It allows Keyaru to heal wounds and injuries. That includes injuries he himself has sustained. This ability is so potent that it can even recover severed limbs, but it has one great drawback. Using Recover forces Keyaru to relive the suffering of the person he’s healing, which often makes him collapse. Using it on himself, however, has no negative consequences.

Going hand-in-hand with Recover, Simulation allows Keyaru to copy skills and abilities of people he has healed. What’s terrifying about this ability is that it doesn’t have any cap, meaning the skills and abilities Keyaru steals only stacks up. He also permanently gains these abilities and can use them at will.

Currently, the series has only revealed two stolen abilities that Keyaru has used. First is Kureha Krylet’s swordsmanship. Krylet is both a splendid knight and the first-ever person Keyaru has healed. Back then, Kureha has lost an arm in battle and is rendered incapacitated. Keyaru heals her, which gives him his first taste of Recover’s drawback. Keyaru uses Krylet’s swordsmanship to quickly dispose of the knights guarding Flare.

The second ability is Alchemy. As its name suggests, this ability allows Keyaru to change one form of matter to another. He acquires this ability when he has healed an alchemist who has lost both of his hands. Keyaru uses this ability to escape his jail cell.

This skill allows Keyaru to destroy things simply by touching them. Contrary to what a healing ability is supposed to be doing, this can also be used to destroy humans with a single touch. In fact, this is what he has used to defeat the Demon Lord in his previous life. For his revenge, however, he uses this to destroy his cuffs, as well as Flare’s clothes.

Upgrade has two revealed uses. First, it allows Keyaru to change his appearance. It’s also possible to copy another person’s appearance, as well as alter other people’s appearance. This allows him to set up a meticulous plan to trick the king. After he has escaped from the dungeon, he alters the appearance of the knight who whipped him 30 times into that of himself. Then, he changes his appearance to that of the knight. He frames him and tricks Flare into letting him into her room.

The second function of Upgrade is Memory Erasure. As the name implies, this ability allows Keyaru to erase a person’s memory. He uses this ability on Flare after he changes her appearance. He then baptizes her into a new persona, his lover Freia.

Keyaru’s final ability (yet) and the ability he has been waiting to gain is Toxin Resistance. With this ability, Keyaru is able to break from addiction to the drug Flare was issuing him, which consequently allows him to regain his sanity. The moment he has acquired this ability, he springs into action to start his revenge.