Dr. Mikhail Cossack

Dr. Mikhail Sergeyevich Cossack (Ｄｒ．ミハイル・セルゲイビッチ・コサック Dokutā Mihairu Serugeibitchi Kosakku?, rus. Михаил Сергеевич Казак) is a Russian robotics engineer affiliated with the Stravinsky Science Academy, and lives with his daughter, Kalinka. His hobby is watching ballet.

Mega Man 4
In Dr. Cossack's debut, he sent a letter to Dr. Light stating that he has created eight Robot Masters (consisting of Bright Man, Dive Man, Dust Man, Drill Man, Pharaoh Man, Ring Man, Skull Man, and Toad Man) and sent them to take over the world, in order to show the world his genius. Mega Man set out to defeat the eight new Robot Masters, and made his way to Dr. Cossack's Citadel. Just as he defeated Dr. Cossack in the Cossack Catcher, Proto Man appeared with Kalinka and revealed the truth: Dr. Wily had kidnapped Kalinka and forced Dr. Cossack to work for him as ransom.

Mega Man 5
After Dr. Wily's defeat in the previous game, Dr. Cossack built a robotic bird called Beat for Mega Man to assist him in protecting the world. Dr. Cossack does not appear in the game, only being mentioned in the manual as informing Mega Man of Light's capture, and increasing the firepower of his Mega Buster's charged shot. In the Rockman Complete Works version of Mega Man 5 and its port in Mega Man Anniversary Collection, Cossack serves as the main guide in Navi Mode.

Wily & Right's RockBoard: That's Paradise
Dr. Cossack is one of the playable characters. His objective is to build a new lab to continue his experiments.

Rockman ×over
Dr. Cossack, along with Dr. Light, is responsible for the creation of the Reploid OVER-1, the main protagonist of the game. He appears in Battle Memory.