Malice was build up overtime on a timer (and faster if you attack someone) giving globale raw damage buff and boost DJ damage until the mark go off (fun fact, you get bonus damage even on non-marked target).
It was gimmicky because you just mark someone and then afk stealth until malice is full charge to then burst.
On rifle, kneel was a 2 ammo 10sec base cd (and it stealth), it was nearly unplayable in PVE and in PVP Daredevil D/P was farming it just by spamming headshot.