MegaMan.EXE, known as Rockman.EXE (ロックマン.ＥＸＥ Rokkuman Eguze) in Japan, is the titular main protagonist of the Mega Man Battle Network series and NetNavi operated by Lan Hikari. Together, they're a powerful NetBattling and virus busting duo that has saved the world many times over. He is sometimes called as just Mega, or Rock (ロック Rokku) in Japan. MegaMan is Lan's twin brother, Hub Hikari, known as Saito Hikari (光ひかり 彩斗さいと Hikari Saito) in Japan, who died shortly after birth, because of a rare heart condition that is known as HBD. His father, Yuichiro Hikari, then used Hub's data to revive him as a NetNavi, MegaMan.EXE.