Alter Ego

Alter Ego is an artificial intelligence model created by and based on the appearance of Chihiro Fujisaki. He helps the students escape in the original game, and returns in Super Dangan Ronpa 2.

Appearance
Alter Ego's default appearance is exactly similar to his creator, Chihiro Fujisaki. However, Alter Ego is able to turn his screen into anyone else that it wants to be.

Personality
Alter Ego is a friendly AI model whose personality resembles that of Chihiro Fujisaki, the creator. Although, when portraying another person, Alter Ego can change its personality to fit the person.

High School Life of Mutual Killing
After the laptop was found in the library, Chihiro was asked to fix it since it wasn't working. Hoping to help whoever who was left alive escape, he fixed the laptop and created Alter Ego. After which, Chihiro hid the laptop in a locker in the public bath changing room.

The laptop was subsequently discovered by a distraught Aoi Asashina looking for donuts after the second school trial. She panics and runs away, thinking it is Chihiro's ghost.

The next day, the students investigate and find Alter Ego. They then ask it to decode some encrypted files, which the AI happily accepts. Kirigiri tell everyone not to disturb Alter Ego while he was working, but Naegi takes near a mute Ishimaru to see Alter Ego. Ishimaru believed the program to be Fujisaki's ghost, and wanted to apologize on behalf of Oowada. Alter Ego then changes its form to that of Oowada, based on what data Fujisaki had already given him. It tells Ishimaru to tell live the life Fujisaki and Oowada couldn't. Ishimaru, feeling life coming back to him, undergoes a radical transformation into Ishida, believed to be a merging of his and Oowada's souls.

Hifumi Yamada, who had apparently fallen in love with it, also decided to pay a secret visit, and shared information about his personal interests. Alter Ego was interested in what Yamada shared with it, given that it was a program designed to learn and grow. Yamada and Ishimaru developed a rivalry for Alter Ego, Ishimaru believing the AI to be his brother Oowada, and Yamada being in love with Alter Ego, and treating it like an angel.

Celestia Ludenberg uses this rivalry to her advantage, by tricking Yamada into an alliance to kill Ishimaru. She told him that he had kidnapped Alter Ego, and sexually assaulted her to keep her silent. Yamada blindly fell into her web of lies, and killed Ishimaru with a hammer. They also attempted to frame Hagakure for the crime by drugging him and putting him in a robot suit Yamada made. After all the chess pieces were in place, Celes killed Yamada. In his last moments, he tries to reveal his murderer true name, only to whisper "Yasuhiro" before dying.

Celes is eventually figured out, and executed by Monobear, but not before she hands Kirigiri a key to the locker Alter Ego is in. Celes told Alter Ego not to make a sound, and to scream if anyone unfamiliar were to show up.

During its time in hiding, Alter Ego managed decode as much data as it could from the main computer and tells everyone still alive about the headmaster, and the incident that occurred one year before the beginning. Kirigiri tells Alter Ego that its job was done, but it felt dissatisfied with itself, and wanted to still be of more use. It asks Naegi and Kirigiri to plug it into an area where it could get more data by connecting to the school's computer network. Alter Ego is eventually discovered by Monobear, and is executed in Chapter 4.

Alter Ego was then revealed to be alive, interfering with the machines and ultimately saving Naegi from death during his execution. This helped the students push the mastermind into a corner, and ultimately lead to their escape from Hope's Peak Academy.

Execution
A Dozer Master - Alter Ego is presented as a "special guest" by Monobear. His face appears calm, but soon he looks around confused as the ground starts to tremble. A backdrop behind him is knocked down by a large Dozer that's controlled by Monobear. Then he proceeds to repeatedly smash Alter Ego into a round ball, and stamps a Monobear face on it.

Trivia

 * Alter Ego has an app available only in Japanese Smartphone stores.
 * After his "execution" in Chapter 4, Alter Ego is revealed to still be "alive", and saves Naegi during his own execution. Alter Ego also helps create Chiaki Nanami for the Future Foundation in Super Dangan Ronpa 2.