The X-Men character with blue fur is BEAST, a mutant superhero with superhuman strength, agility, and endurance. He is a brilliant scientist and a founding member of the X-Men. His real name is Hank McCoy and he was born with blue fur and feline features. He has the ability to think and reason at a superhuman level and is a master of hand-to-hand combat. BEAST is a loyal friend and ally to the X-Men and is often seen as a mentor figure to the younger members of the team.