>>532619797
M1 killers are those that are reliant on their basic attacks to injure, down or apply pressure to the map.
Trapper in an M1 because traps are not pressure, since they neither move nor have intrinsic danger by themselves.
Pig is an ability killer, since her rush breaks through the stealth so strongly, then hits survivors. Her reverse bear traps also have the intrinsic pressure of death by gens.
Ghostface and Myers are both easy M1 killers, as their pressure is exerted by only applying exposed to survivors, still needing M1 to down. Mirror myers however is in a different camp, as he gains such a different ability then, same with tombstone.
Believe it or not, Legion is M1, as the ability to apply pressure at all is reliant on hooks for him, since injuring is a nonissue.