Kraven

Kraven the Hunter (real name Sergei Kravinoff) is a lethal hunter and a member of the Sinister Six.

Ultimate Spider-Man
At some point in the past, Kraven killed Hector Ayala, the former White Tiger.

Kraven first arrived in New York and started to antagonize Ava Ayala from afar. First was during a training session with her group, in which he caused her to act chaotic and run rampant. However, Ava was not easily fooled and knew he was behind it. During her attacks on New York, her team chased after her. However, Kraven appeared before the entirety of the group sans Ava and another and defeated Nova and Iron Fist with a knockout dart. As Power Man moved in to attack him, Kraven easily took him out with his knockout gas.

He soon stole the Tiger Amulet, but was transformed into a humanoid tiger. Ava and Peter removed it and White Tiger almost finished Kraven, but Spider-Man stopped her by telling her his own experience with the burglar who killed his uncle.

He was later hired by Doctor Octopus to be part of the Sinister Six and fought White Tiger, but was defeated by Power Man and jailed in the currently rebuilt S.H.I.E.L.D. Helicarrier.