Rexxar's trusted companion, Misha, is a magical bear who will fight at Rexxar's side whenever she is called upon. Misha battles ferociously, and loyally follows Rexxar to every location he travels to. Rexxar is very protective of Misha when they enter civilized areas, and ensures that the bear stays close to him.
"Misha" is a common Russian name (full version is "Mikhail", anglicized to "Michael") which usually was given to bear characters in fairy tales, perhaps because of its similarity to "medved", which means "bear" in the Russian language.
"Misha" or "Mishka" is also a tender synonym for a bear cub or a cute bear, often used in informal speech. Thus, contrasting the character's ferocious outlook, it sounds funny enough for a Russian ear.
Misha was also the name of the bear mascot of the 1980 Moscow Olympic Games.