Ryota Mitarai

Ryota Mitarai is the final main antagonist of Danganronpa 3: End of Hope's Peak High and the fourth main antagonist of the entire Danganronpa franchise. He first starts off as a character with a moral code, but eventually loses his mind after finding out Kazuo Tengan planned on making the entire Future Foundation turn on each other. He tries to brainwash the world eliminate despair entirely.

Pre- Future Foundation
Ryota Mitarai was a scrawny kid who was always made fun of at school. When his parents started to argue about his well being, Mitarai would sit down in front of a T.V. and watch anime. He decided then that that was what he wanted to do with his life. When he was accepted into Hope's Peak High, he did not want to attend classes to finish his anime. This got so bad that he would refuse to eat. One day, after collapsing from a food withdrawal, The Ultimate Imposter showed up to help him and become him. With Mitarai's consent, The Ultimate Imposter took up the identity of Ryota Mitarai while the real Mitarai finished his anime. One day Mitarai almost died of not eating that The Ultimate Imposter had to get The Ultimate Nurse to come in and heal him up. The Nurse said that he needed to eat more and go to the doctors for a usual check up. One day, when he was going in to get a check up, He ran into Junko Enoshima. Junko realized that she could use Mitarai anime to hypnotize people into believing in despair. After Mitarai saw what Junko's despair video he panicked and tried to run away, only to be stopped by The Ultimate Nurse, who was hypnotized by Junko's videos. When Chiaki Nanami shows up to find The Ultimate Nurse, Mitarai uses this time to flee where he is being held. When he is stopped by a bunch of other students, he is confronted by Junko, who thanks him for making the video. After this, Mitarai runs away and falls into the river.

Future Foundation
Miter mostly serves as a protagonist in The Future Arc.

Mitarai joined Kirigiri's team when the Final Killing Games began. After Kirigiri Died, Mitarai showed his distrust in Naegi. After Naegi talked to Mitarai, he seems to have calmed down. His true villainy begins after they destroy The Masterminds plan. Mitarai gets a message from a Posthumous Kazuo Tengan. In the message Tengan confirms that he is The Mastermind and he was using Mitarai as a pawn. Hurt by this, Mitarai runs out of the room and hypnotizes a couple of guards in the process. He sends them to kill Nag's group. After this he makes it to a broadcasting station and begins broadcasting the video to the entire world.

Defeat
Within minutes of the video almost being done Mitarai is confronted by the 77th class. Mitarai tries to explain to them that what he is doing is the right thing, but they convince him that a world without despair would be boring. With just 3 minutes and 30 seconds left, a tear soaked Mitarai pushes the cancel button and collapse into tears on The Ultimate Imposter. Mitarai is last seen on the boat as everyone is celebrating. Miter drops his phone into the ocean, destroying the video and Tengan's plan. It is most likely that Mitarai went to live on Jabberwock Island with the 77th class