(Reoccurring Role) Bruce Banner, the brilliant scientist and Hulk the embodiment of rage and loneliness. Bruce's origin story is often changed, so I'll stick with the one that correlates with this Avengers. Bruce was tormented as a child by his father, which caused trauma in his Psyche. This trauma came to fruition when he was exposed to gamma radiation when trying to save his good friend Rick Jones. As a result, whenever he loses emotional control he changes into the Hulk. However, over time he's learned to master his emotions and actually uses the Hulk as a tool. The two personalities became one and they both have a goal in making the world better. 

Voice - Banner's voice need to be medium and should sound calculating. Hulk's voice should be low and monstrous, but should also be understandable when he talks.