Bloodfeather

Bleeding Edge. Once per turn the Bloodfeather adds 10 (3d6) necrotic damage to its shortsword attack, if it used its Bloody Step ability in the same turn.

Mimicry. The Bloodfeather can perfectly mimic sounds it has heard before. A creature that hears those sounds can tell that they’re imitations only with a successful Insight check (DC 16)

Spellcasting. The Bloodfeather is a 5th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 14, +6 to hit with spell attacks). The Bloodfeather has following wizard spells prepared:
Cantrips (at will): prestidigitation, shocking grasp, minor illusion and lightning lure
1st level (3 slots): disguise self, absorb elements and snare 
2nd level (1 slot): darkness

Multiattack. The Bloodfeather makes two shortsword attacks.

Shortsword. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 8 (1d6 + 5) piercing damage.

Hide. While in dim light or darkness, the Bloodfeather takes the hide action.

Bloody Step (Recharge 4-6). The Bloodfeather teleports up to 30 ft. to a space next to another creature. It must stand within 5 ft. of a target that is missing any hit points to do so.