Rewrite (リライト riraito) is the titular superhuman ability to irreversibly enhance one's abilities, possessed by the protagonist Kotarou Tennouji. The ability is also sometimes called kakikaeru (書き換える, lit. "rewrite") or uwagaki nouryoku (上書き能力 lit. "ability to overwrite").
Rewriting allows one to increase his physical abilities by willing his body to change. The change can come in the form of obtaining greater physical strength, quicker movements, stronger senses, or higher intelligence. The change, often drastic, can disorient the user, causing a temporary unpleasant feeling.
These increases are permanent and irreversible. If the user increased his strength through it, the strength will remain, and can make it difficult to control. In one case, Kotarou accidentally broke a doorknob.
In the visual novel and in the first opening of the TV Anime, the ability is represented by a gear and dial. The pointer will move further for every time the ability is used. Halfway through, the gear will start glowing pink. The cursor going out of whack indicates that the ability has been overused and the user ceased to be human. This has happened in Chihaya Route. The user's loss of the power is indicated by the cursor rolling back counterclockwise and then disappearing, as seen in Kotori Route. The gear and dial does not appear in Moon and Terra.
It is later explained that rewriting consumes the user's life energy in exchange of power. Overuse of the ability will cause not only death, but will also turn the user into a familiar. In this case, his body will turn into a tree. He can be summoned by someone capable of doing so.
The birth of a Rewrite user is often said to be a reaction to the birth of a Key.
- Sakuya had already used this ability many times before the current story but the first time showed is when he strengthened himself to protect his former master, Minata.
- The second and time Sakuya uses this ability is when is when the Key emits salvation, causing everyone, even Minata, to disappear. While drowning in despair, he rewrites his body into a cherry blossom tree.
- When Kotarou was a child he was being bullied by other kids but had always hesitated to fight back until he decided to get even. He rewrote his entire body to get stronger and ended up sending the bullies to the hospital. With the parents of those children furious, Kotarou's parents moved to Kazamatsuri.
- While still in elementary school a very athletic child always bragged to the other children about how good in gym class he was. Kotarou rewrote his body again to the point that he could run as fast as or jump as high as a highschooler. However, this caused problems for Kotarou as his stunts attracted 'media' attention so he had to painstakingly work to make himself seem like a normal child again.
- Kotarou doesn't use his ability in Kotori's Route, except at the end of the Common Route when he and the heroines encounter the Leaf Dragon in the forest.
- Kotarou's right hand was excessively large so he takes Sakuya's advise and rewrites the oppisite hand so they are both equal. He also uses the rewrite ability as a strength boost twice, the second time his whole body. He evidently used it when training with Sakuya, as a consequence his gear/deal changes a great deal.
- When battling Midou Kotarou enhances his strength, improving his damage done to enemies. He even uses it to anneal himself once again; making his skin able to grow back after being burnt off and increasing his strength so that he can break through Midou's shield.
- When cornered by Touka and Shizuru, Kotarou is forced to rewrite his mind doing so causes his rewrite ability to spin out of control. His body's strength and speed exceed Sakuya's but he has no control over his body and attacks even his allies. He uses this ability again at the end of the route, only this time he is in control of himself.
- Sakuya uses this ability to rewrite Kotarou's mind back to normal when he's out of control, not only stabilizing him but also sharing part of his memories with him.
- Kotarou makes an important decision to rewrite his body so that it can accept Lucia's curse/poison.
- He uses it to resist against the poison that Lucia spread all over Kazamatsuri.
- He rewrites his body to that it is unable to be cut by Lucia's sword.
- Kotarou uses the rewrite power to strengthen himself. He rewrote himself a second time as well, in order to defend himself against a group of familiars.
- Lastly, he rewrites himself so that he transforms into a tree, so that his body is not annihilated by salvation.
- When facing a strong opponent, Kotarou uses his rewrite ability to improve his physical combat skills so that he can withstand Takasago's strength.
- He later uses the power to fend off five hounds. Not too long after he subconciously rewrites himself due to the anger rising in him.
- In the tunnels of Gaia, Kotarou rewrites himself to let him see in the dark.
- When Takasago challenges him, he powers himself up again.
- In an effort to defeat theEarth Dragon, he continuously rewrites his aurora so that it is able to harm the dragon.
- In the route Kotarou actually rewrote himself mentally, increasing his knowledge and enlightening his understanding of the world around him. However, he ascends too far into the peak of existence and is unable to come back down. The Moon Kagari pulls him down with her ribbons.
- Kotarou starts to rewrite himself after his commander kills two wounded children and hits him for being sentimental to their enemies. He attempts to rewrite himself with the intent to gain the strength to crush the commander's skull, but Luis stops him.
- After Luis sacrifices himself to shoot down three missiles that could kill him and the three children he was carrying, Kotarou rewrites to give himself animal instincts so that he can cross the barren terrain with ease while carrying the three children (Jasmine, Midou, and Tenjin).
- When Guardian goes all out to enter the forest in order to capture or kill Kagari, Kotarou rewrites himself so that he can destroy the helicopter in the sky with a spear. He then rewrites himself again to escape from the hunters.
- He rewrites himself so that he can fight against a younger Sougen Esaka.
- Kotarou rewrites himself so that he can fight the Earth Dragon.
- After he sees that Iko, Sakura, and the disciples are dead, Kotarou jumps off of Gaia's tree structure and lands on the ground; destroying one of his lungs in the process. He rewrites himself to regrow his lung and creates another artery near the heart in order to avoid air embolism.
- Kotarou used his remaining life to rewrite his body so that he is able to reach Kagari in the daisy hill as fast as he could. This caused him to turn into a familiar soon after meeting Kagari for the last time.
- We only see examples of mentally rewriting in Chihaya's Route and in the Moon Route.
- When Kotori cuts the summoner-familiar link with Kotarou, Kotarou loses all the changes to his body as well as his rewrite ability altogether.
- The Rewrite Ability, philosophically speaking, represents the will humanity has to carve open or "Rewrite" the future for better or for worse.