Camper! - Get 2 sniper headshots without unscoping or switching weapons
Be The Bull - get 5 kills with a shotgun without switching weapons
Ashes, Ashes - get a precision kill with a fusion rifle (I don't even know if this is possible)
Eliminated - kill a whole fireteam of 3 with 1 bullet
Bumper Cars - pop a Defender's bubble with a Fist of Havoc
Raaaiiiinbooowww - map someone with a Nova Bomb
Nice Pitch! - Map someone with a Hammer of Sol
Butter Knife - kill a Blade Dancer while inside your bubble and/or buffed by Ward of Dawn
Emperor Palpatine - get 3 kills with Stormtrace while on critical health
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XD eliminated would be LEGENDARY