Grey is a muscular wolf who wants to become the pack's new leader to gain some respect from his peers However, even though he is the pack's favorite wolf, he is considered a comic relief by many. In order to become leader and win back his love interest, Bianca, Grey goes off into the woods, where he discovers a camp of Gypsy rabbits, Mami and Baron. The fortune-teller rabbit Mami gives him a magical "transmutation potion." Grey drinks the potion and goes back to the wolves' den, but finds out upon arrival that he has been accidentally transformed into a ram, much to his horror. Grey goes on a adventure to change back to normal and prove himself worthy to his pack.

Grey is a wolf who has a well-built body. He also has grey fur, hence his name, but with white linings.

From source: https://en.wikipedia.org/wiki/Sheep_and_Wolves#Wolves

Alexander Petrov) (Russian) and Tom Felton (English dub) as Grey.
Grey was Petrov's first voice role, and he had considered leaving the film after his first recording takes for the character were unsuccessful. However, he was persuaded by director Maxim Volkov to keep practicing his voice talent and started enjoying working for the film.