Kovalev. Usually when a fighter kills another man in the ring, it takes the edge off their game and makes them gunshy. Affects them deeply. I'm not saying Simakov's death didn't affect Kovalev deeply outside of the ring, but you'd never know it by how he fights now. If I didn't know any better, it looks like it's just given him bloodlust.
Everytime, every single time that Stevenson is asked about a fight with Kovalev, his eyes go from fixed on the interviewer to looking for the door. Kovalev is such a beast that he literally sends Stevenson into a PANIC ATTACK at the mere mention of his name. GGG.......guys are afraid to take their KO losses to him, but at least GGG KOs some guys to the body.......KOvalev straight up tries to take their heads off.:yep
Monzon deserves a mention, a cold ruthless mofo Currently active, Chisora seems to be rather unhinged & I've read that Vic Darchinyan is absolutely nuts
Edwin Valero was quite intimidating, despite his small stature. You just knew he was not to be fvcked with, he had a very cold stare.