[Crossover + no heroine + merged worlds + all out-of-character portrayals are author-created]
Akagi Sora realizes at the age of four that he is a transmigrator. Just as he thinks he must be the protagonist of this world, he discovers that its style is steadily veering away from what he expected.
Akagi Sora: There has to be something wrong with this world!
P.S. This crosses over with many worlds. Find them for yourself.
