Mikhail Uriokovitch Ursus, also known as Ursa Major, is a Marvel Comics character and a member of the Winter Guard. He appears in the Marvel Cinematic Universe, in Black Widow portrayed by Olivier Richters.
Ursa Major was created by Bill Mantlo and Sal Buscema.
When the Winter Guard have operated against the direct orders of their superiors to rescue and retrieve one of their comrades trapped in a special container appearing to be a bomb with the key needed to release him. Their operations soon earned the attention of S.H.I.E.L.D. which Nick Fury have sent the breakaway group of Avengers under Captain America to deal with them now while kept them in the dark of the Winter Guard's true intentions.
This led to clashes between the Winter Guard and Captain America's Avengers over the key until at the facility where they fought began to collapse and threatened to destroy the nearby village, forcing both groups to work together until Crimson Dynamo and Falcon released Radioactive Man from his prison and melted the collapsing facility down.
After the crisis has been averted, the Winter Guard then revealed the true purpose that they did everything they can to save their comrade and wouldn't want Radioactive Man to be used as a weapon, something that the Avengers can relate with the Hulk.
When Alexei Shostokov is locked up in the Gulag, one of his inmates is a man named Ursa. Ursa challenges him to an arm wrestling match as he mouths off a past encounter with Captain America. When Ursa points out the inaccuracy with his story, Alexei breaks his arm before calling him a "little bear" for whimpering.
- Olivier Richters confirmed on Instagram that Ursa Major is the first mutant introduced in the Marvel Cinematic Universe.