Face Off! 
After you’re done with your festivities in the Tower, you still have plenty of work to do for Eva. As soon as you finish the Trick-or-Treating quest, you will open up three more quests from the NPC. The first of which is “Face Off!” — which as you guess it, is Crucible focused.
You’re tasked with getting 30 kills while wearing a Engram mask (doesn’t matter which) and 5 sword kills while wearing the Crota Mask (fitting isn’t it?). The kill portion shouldn’t be a problem as long as you have the mask, definitely play Rift for that portion. As for the sword kills, you will have to just be patient. Plenty of other Guardians are trying to achieve this in Multiplayer, so expect heavy resistance for the precious heavy ammo drop.
Your reward: “Gifts of the Lost” again. A Random Rare Mask, Random Festival Candy and all sorts of random goodies. Maybe a Jackolyte or Flight of Shadows.
