Not every Marvel character is righteous enough to avoid killing. Here are a few of them who have some blood on their hands. Check it out. You'd be surprise with the amount of kills too.

Who he's killed too:

Yellow Jacket
Mallen
Majestor/Gladiator

Who he's killed too:

Cortez
The Insect
Zala Dane

Who he's killed too:

Professor X
Bezerker
Donald Pierce

Who he's killed too:

Master Khan
Marrina/Leviathan
Hatchet Man

Who he's killed too:

Red Skull
Baron Blood
Harry S. Truman

Who he's killed too:

Hybrid
Hijacker
Death Addler

Who she's killed too:

Christian Wagner
Graydon Creed
Mr. Sinister

Who he's killed too:

William Stryker
Commander
Famine

Who he's killed too:

Mr. Immortal
Anthony Sardo
Butcher

Who she's killed too:

Alchemist
Scrambler
Matthew Risman

Who he's killed too:

Feral
Silverfox
Copycat

Who he's killed too:

Janet Van Dyne
Uriel Worthington
Ragnarok

Who he's killed too:

Vulture
Stilt-Man
Wraith

Who he's killed too:

Weapon III
T-Ray
Agent X

Who he's killed too:

Jean Grey
Mystique
Daken