Shadow the Hedgehog

Shadow the Hedgehog is a major character who starts out as Sonic's sworn enemy in Sonic Adventure 2, but he ends up to befriend Sonic, and their animosity was toned down somewhat into a rivalry.

Personality
Being Sonic's double-ganger, Shadow exhibits large scares of both similarities and differences to him. He can be cocky and snarky like Sonic, but is also stern and doesn't have the carefree, optimistic additude that Sonic has. Losing his only friend, Maria, had shaped the way he acts, and had turned him into a bitter, and power-hungry misanthrope.

Despite being heartbroken due to Maria Robotnik's death, Shadow is still very proud of himself being the Ultimate Lifeform and likes to have others pay attention to it. He also tends to have quite a complicated relationship with Sonic. He generally likes getting him in trouble, and attacking him when he's weak. However, he will help him when fighting an enemy, and considers him a worthy opponoment.

Despite his inferioty complex and hatred for humans, Shadow still cares about people deep down, and will thank those have helped him in anyway. He will also help anyone who's in trouble, yet attempt to hide his concern of them.