Cossak (コサック Kosakku) is a character from MegaMan Battle Network 3. He was Bass.EXE's NetOp and creator.
History
When he worked at SciLab, he was in charge of the project that created Bass. Cossak tried to make an AutoNavi, a NetNavi that could operate on its own without a NetOp but when Alpha began malfunctioning, he was blamed. Bass was assumed to have been deleted but survives. Cossak was arrested but was released at a further point in time.
MegaMan Battle Network 3
Years later, he tries to stop Bass in MegaMan Battle Network 3. Dr. Cossak is seen during the FlashMan arc, at night. If he is talked to, he warns them not to stay out late. Cossak is walking to the ACDC train station when Chisao arrives. He asks for directions but Cossak tells him he has to go to a meeting and leaves. He also appears during BubbleMan's attack, where he helps Lan modifying the PET to allow MegaMan pass by small areas. When MegaMan fights against Bass in the Undernet and is knocked out, Cossak's NormalNavi appears to fight against Bass, being almost deleted, but Bass leaves when Wily called for him saying he has the four TetraCodes. Cossak hears this and suspect they are trying to awaken Alpha. In the WWW's base, Cossak appears to help Lan, Tora, Chaud and Dex. Dr. Cossak explais his past and connections with Bass and then transmits himself into the Cuberworld. He is opening a pathway when Bass arrives and attacks him. In the ensuing battle, Cossak is badly injured. He's taken to the hospital and Lan tells him what happened in Castle Wily. Some speculate that Cossak survived because Bass couldn't bring himself to kill his former partner.
Later, he is briefly mentioned after MegaMan defeats Bass in Secret Area. MegaMan reminds Bass of Cossak. Despite his amnesia, he seems to remember slightly but leaves.
Manga
Like the games, Cossak was in the project that created Bass in the MegaMan NT Warrior manga. He appeared in a side story telling Bass' origins.
Trivia
Although he has the same Japanese name from his original counterpart, his name was translated without a "c" in the MegaMan Battle Network series.