Mega Man Battle Network (Video Games)

Mega Man Battle Network, known in Japan as Rockman.EXE (ロックマンエグゼ Rokkuman Eguze), is one of Capcom's Mega Man series and debuted in 2001 on the Game Boy Advance. It is a RPG spin-off series based on the original Mega Man series, taking place in a separate continuity where computer and networking technology advanced instead of robotics.

There are six main Mega Man Battle Network games as well as several side-story games.The series were also adapted into anime (MegaMan NT Warrior) and manga.

Network Transmission (GameCube)
The Navis are infected by the Zero Virus that makes them turn rampage and attack other Navis.

Battle Network 3 Blue/White
Flashman use hypnosis on Lan's Friends

Battle Network 4 Red Sun/Blue Moon
Nebula has been selling Dark Chips that transform Navis into Dark Versions that obeys Nebula.

When MegaMan.EXE has low HP a Dark Chip appears.

Battle Network 5 Team ProtoMan/Team Colonel
Nebula returns together with the Dark Chips. Throughout the plot, MegaMan.EXE got kidnapped and transformed into Dark MegaMan.EXE through the use of the Dark Chips. After rescuing MegaMan.EXE, Colonel/ProtoMan is also turned in Dark ProtoMan or Dark Colonel.

At the end of the game, Willy erase all the memories from Dr.Regal in order for his son to have a normal life.