MegaMan.EXE, known as Rockman.EXE (ロックマンエグゼ, Rokkuman Eguze?) in Japan, is the NetNavi (short for Internet Navigator) operated by Lan Hikari. He was created by the scientist Yuichiro Hikari, Lan's father. MegaMan.EXE is quite powerful, and along with his operator Lan, is a very skilled virus buster. He is also Lan's twin brother, Hub Hikari (Saito in Japan) who died at birth, because of a rare heart condition known as HBD. Dr. Hikari then used his data to revive him as a NetNavi, MegaMan.EXE.
MegaMan is very loyal to Lan and is willing to sacrifice himself to save him in MegaMan Battle Network 3. Their friendship also allows for powerful abilities like Full Synchro and Cross Fusion. MegaMan is also more responsible than Lan, reminding him to do his homework and waking him up in the morning for school. They do argue sometimes like in MegaMan Battle Network 2 but they always manage to reconcile. In the anime, he also displays a fear of ghosts, which doesn't appear in the games.