There are a lot of skills in the skill trees of the characters, that are stated as a "Kill Skill", like "I'm the Juggernaut" from Salvador. There is also stated that they are triggered by a kill ("Killing an enemy gives +4% Damage Reduction for a short time." on the "I'm the Juggernaut" skill).
I'm now interested in when are they triggered on a coop-play. Does the kill from my mate also count to this skill or is it related just to my kills?