Keyaru

Kearu (ケヤル), also known as Keyaruga (ケヤルガ), is the main protagonist of Kaifuku Jutsushi no Yarinaoshi series.

After years of torture at the hands of his own allies, he manages to break free and get the Philosopher's Stone. He then uses the item to go back four years time to exact revenge against the people who tortured him.

Appearance
Kearu is a young boy of medium height with brown hair and red eyes. Initially he is dressed in simple clothes he used in the village, then after the start of his revenge he uses a set of armor he stole from the Captain of the Guards. When he uses his Heal skill, his eyes turn green.

Pre-Betrayal
While little of who Kearu was before the betrayal is shown, he used to be a kind and simple boy with dreams. After realizing that he was a hero he was excited to save the world, and although he was very different due to his class he was still happy and didn't realize Flare's true intentions for him until it was too late.

Post-Betrayal
After being imprisoned, tortured, drugged and raped, his personality changes completely to that of a vindictive and sadistic individual. Because his naive personality allowed him to be taken advantage of, he changes to become a manipulative and cunning misanthrope full of hate towards those who abused him.

Revenge is Keyaru's primary concern, although at least once he has mentioned the possibility of "living happily" once he has taken vengeance on his abusers. When asked why he seeks revenge, he says that the idea of people he hates being allowed to peacefully exist without consequences is disgusting to him. Contrarily to someone like Setsuna, he thoroughly takes pleasure upon taking vengeance, as seen by his happy laughter after having raped Flare and erasing her memories. The exception to this is the Knight Captain as even after the elaborate torture Keyaru devises for him, he displays no happiness nor satisfaction during it nor afterwards, presumably because the Knight Captain's actions resulted in the death of many of Keyaru's loved ones.

One of Kearu's redeeming factors is that he has no desire to harm those who have done him no harm, and in fact makes it a personal rule not to drag them into his revenge; this applies even to people who are otherwise cruel like Princess Norn (until he discovers that she had a hand in executing the captured members of his village). Keyaru also has some sympathy for people who strive for justified revenge the same way he does, and will do his best to help grant them their desire with the condition that they also help him with his.

His relationship with the members of his party is hard to read. On the one hand, he commonly refers to them as his "toys" or "playthings" in his inner thoughts, implying that he has no real love for them and only sees them as tools. However, aside from some relatively very minor things (such as having Freia carry his luggage in revenge for formerly serving as the pack mule), he normally treats them only with kindness, completely at odds with his own treatment at the hands of Flare's party, and gets very agitated when one of them is harmed. Whether this means that he is more protective about them than one might think or simply possessive is unclear.

Previous Timeline
As he was one of the chosen heroes, Flare Arlgrande Jioral took Keyaru to Jioral Kingdom, where he identified himself as the Healing Hero. Unfortunately for Keyaru, prejudice against the healer class resulted in Flare, the Heroes and Jioral Kingdom abusing and torturing Keyaru to the point where he was addicted to a healing drug Flare fed him to keep him in line. Developing an immense hatred toward them, he eventually develops a resistance to the drug and is able to maintain his sanity. When the heroes are incapacitated by the current Demon King, Keyaru is able to defeat him with ease and reveal him to be a silver-haired woman. Using the Philosopher's Stone he obtained from her, Keyaru declares vengeance on Flare before reversing time by four years.

Current Timeline
After waking up in his village, Keyaru goes into the woods and obtains the ability to read statuses of other from the spirit of the stars. He then eats numerous toxic mushrooms to develop his poison resistance and goes back to the village to be picked up by Flare the next morning.

After arriving at Jioral Kingdom, Keyaru notes that he is too weak to challenge any of the soldiers. A female attendant rapes him in his room to increase her level cap, so he takes the opportunity to steal some of her experience. Remembering that he has to restore Kureha Clyret's arm the following week, he plans to take some of her experience as well. When he is finally called to restore her arm, Keyaru pretends to faint to get a look at Flare's reaction. Upon seeing that she gave up on him the first time he used his Heal ability, Keyaru takes delight in how he won't feel guilty taking revenge. Later, Keyaru is given a cup of poisoned tea by Flare. His attempts to convince her otherwise fail so he is forced to drink it, rendering him unconscious. In confinement, Keyaru steals experience from soldiers raping him to increase their level cap, and acquires drug resistance to prevent him from succumbing to Flare's drug.

Keyaru escapes his prison cell after one month of captivity. After evading the guards under the guise of a knight, he exacts vengeance on the captain of the knights by besting him in combat and transforming his appearance to look like Keyaru's, before transforming himself to look like the captain. Utilizing his disguise, Keyaru is able to get isolate himself and Flare and subject her to prolonged torture after revealing his identity. He then makes her submit to rape by making her choose between that and being burned by a metal rod. To complete his revenge, he transforms her appearance to suit his taste and erases her memories. After arriving at an inn with the amnesiac Flare, he convinces her that she is his slave and lover before the two have passionate sex.

Powers & Abilities
Heal:  By healing things and concepts, Keyaru performs various abilities from the Healer Class: Eye of Truth:  Also called as "The Eye That Sees Through Everything", is a powerful magic that Keyaru obtained by making a pact with the spirit of the stars. It allows him to get full information about the target's stats, such as: Magical defense, Physical defense, Level, Mana, Health, Class, Abilities, Passives, and Speed.
 * Recover: By manipulating time and matter, Keyaru can return things to their original states and heal deep injuries from himself or others. Initially, using it to heal someone would cause him great pain, but later on he learns how to use this skill without showing any signs of pain at all.
 * Simulation: Every time Keyaru heals someone, he gains the fighting skills and experience from that person. He already used this skill many times before, retaining all the knowledge from different fighters, soldiers and mages.
 * Corruption: Destroys the target from inside by corrupting them. Keyaru usually refers to this ability as a One-Hit KO skill.
 * Steal: Can either absorb or copy some of the levels of a person, allowing Keyaru to level up. The same ability can also be used to absorb all the mana from someone, or just a portion if he wants. If the target is a mage or fully dependent on mana, that person gets incapacitated and weakened.
 * Upgrade: Ability that allows Keyaru to modify things by "upgrading" them to a desired state.
 * Superhuman Augmentation: By upgrading himself, he can change his stat spread by enhancing some stats (such as strength, speed, magical defense, physical defense, and magical attack) at the cost of reducing others. He cannot, however, change his stat total.
 * Transmutation: This allows him to change an individual's appearance, physical stats, gender, and mind.
 * Memory Erasure: While touching someone's head, Keyaru can change the memories of an individual and can also erase them at will. He can also force the target to experience memories, as shown with Kureha Clyret.
 * Shapeshift: By using Upgrade on himself, Keyaru can change his appearance.
 * Rewrite: Keyaru can use Upgrade on enchanted/magical objects, changing their functions.

Alchemy:  Keyaru is a skilled alchemist. He is able to magically "transmute" matter into other forms, as seen for example when he turns a lead pipe into a key. He is also a capable creator of airborne poisons, such as an aphrodisiac that makes the target too sexually excited to fight, or a deadly paralytic agent. He keeps them in flasks that he shatters against the ground when needed, letting the deadly vapors spread. He also has needles to inject the poisons directly into a target for added effect.

Toxin Resistance:  Thanks to having trained his body extensively by consuming massive amounts of toxic mushrooms and having subsequently shaken off the effect of Flare's drug, Keyaru is immune or incredibly resistant to the effect of most poisons and drugs. This is what allows him to use his alchemical grenades to great effect, as the fumes that are debilitating to others have absolutely no effect on Keyaru.

Level Cap Break: Being one of the heroes allows him to level up as much as he wants without having a level limit as well as increasing the level cap of others. Keyaru does the latter for his party members by having sex with them.

 Intelligence:  Keyaru is extremely intelligent and cunning. He is shown to have an impressive knowledge of magical theory, being able to develop many unconventional uses for his own Heal spell, teach Freia how to best use her magic to her advantage, and rig an enchantment to his own benefit. He is skilled at developing strategies and tactics to ensure that any battle he partakes in swings to his advantage as much as possible. This is best illustrated during his assault on the Arena, wherein he not only infiltrates the place several weeks in advance to stealthily tamper with its defenses, but also develops a plan to swing the hearts of Jhoiral Kingdom's residents in favor of his cause. Keyaru is manipulative and knows exactly which buttons to press to turn a person into a loyal follower, as shown with Setsuna and Eve Reese.

Equipment

 * Divine Armor Georugius: A ring Keyaru formed after obtaining Blade's Holy Armament and forming a contract with it. after forming a contract with it. As long as his mana has not been exhausted, Keyaru can use the armor to automatically heal injuries. The armor also allows him to send spells up to a meter away that would otherwise require physical contact; shown when he used the armor to cast Corruption on Hawk Eye from a short distance.

Etymology
His real name Keyaru (ケヤル), fake name Keyaruga (ケヤルガ), and his feminine name he used while disguising as a girl Keyarura (ケヤルラ), are all similar to healing magics from the Final Fantasy video game series (Cure, Curaga and Cura, respectively), as opposed to Flare's name associating with an offensive magic.

Quotes

 * "The weaker Keyaru no longer exists. I have been reborn. My name is Keyaruga. I will redo my life how I want it. I am strongest healer." -in Episode 2.