Alter Ego

Alter Ego (アルターエゴ Arutā Ego) is an artificial intelligence model featured in Danganronpa: Trigger Happy Havoc. He is created by and based on the appearance of Chihiro Fujisaki, his creator.

In chapter 4, Alter Ego is executed by Monokuma as the replacement of both fourth murder case victim and blackened, Sakura Ogami. However, the virus he planted returned in chapter 5, saving Makoto Naegi from his execution.

Alter Ego also appears in Danganronpa 2: Goodbye Despair as the overseer of the Neo World Program, though it's possible that it was a different one that Chihiro created earlier. It's revealed that he was the one who modified Chiaki Nanami and Usami, the artificial intelligences created by Chihiro, to become moles for the Future Foundation.

Appearance
Alter Ego's default appearance is the face of his creator, Chihiro. However, Alter Ego is able to turn his screen into anyone else that it wants to be. He also has a green color scheme and has multiple applications on his desktop. The second game shows him as a black monolith, with a red outline of Chihiro (and later Makoto) and red text appearing on it.

Personality
Alter Ego is a friendly AI whose personality resembles that of Chihiro, its creator. When portraying another person, Alter Ego can change its personality to fit that person. For example, during their first meeting, Alter Ego mimics Mondo Owada's appearance and personality for Kiyotaka Ishimaru.

Chapter 2 - Boy's Life of Despair
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. Later, Chihiro hid the laptop in a locker in the public bath changing room.

Chapter 3 - A Next Generation Legend!
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. Kyoko Kirigiri tells everyone not to disturb Alter Ego while he was working, but Makoto takes near a mute Taka to see Alter Ego. Taka believed the program to be Chihiro's ghost, and wanted to apologize on behalf of Mondo. Alter Ego then changes its form to that of Mondo, based on what data Chihiro had already given him. It tells Taka to tell live the life Chihiro and Mondo couldn't. Taka, feeling life coming back to him, undergoes a radical transformation into Kiyondo, believed to be a merging of his and Mondo'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 Hifumi shared with it, given that it was a program designed to learn and grow. Hifumi and Taka developed a rivalry for Alter Ego, Taka believing the AI to be his brother Mondo, and Hifumi being in love with Alter Ego, and treating it like an angel.

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

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

Chapter 4 - All●Star●Apologies
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. Kyoko tells Alter Ego that its job was done, but it felt dissatisfied with itself, and wanted to still be of more use. It asks Makoto and Kyoko 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 Monokuma, and is executed in Chapter 4, replacing Sakura who has becoming both as the victim and the culprit.

Chapter 5 - 100 Mile Dash; Pain of a Junk Food Junkie
It's revealed that Alter Ego managed to leave behind a virus in the network before he was executed.

Using his last strength, the virus interfered with the machines and ultimately saved Makoto 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.

Danganronpa 2: Goodbye Despair
Alter Ego returns in the last chapter of the second game, though it's possibly a different one Chihiro created earlier.

Alter Ego works for Future Foundation and exists inside the Neo World Program, working as its master program and overseer. He is also capable of communicating with the outside world. He supposedly modified Chiaki and Usami, the artificial intelligences created by Chihiro, after Chihiro's death. Chiaki and Usami consider him their big brother.

After a virus invaded the Neo World Program, Alter Ego tried to fight it as much as he could. He gave Hajime Hinata some important information regarding the program during the final investigation.

Execution

 * Main Article: Excavator Destroyer

Trivia

 * An "Alter Ego" smartphone application developed by Spike Chunsoft is available for download exclusively in Japanese application stores.
 * Since Alter Ego is programmed to assume by default Chihiro's appearance, voice and, to some extent, personality, they are both voiced by the same voice actors in both the Japanese (Kōki Miyata) and English (Dorothy Elias-Fahn) versions of the game.
 * His English voice actress also voices Sayaka Maizono.