Umberthane

Shape of Shadow. The Umberthane can move through a space as narrow as 1 inch wide without squeezing.

Pack Tactics. The Umberthane has advantage on an attack roll against a creature if at least one of the Umberthane's allies is within 5 feet of the creature and the ally isn't incapacitated.

Eclipsing Howl (Recharge 5-6). The Umberthane lets out a piercing, echoing howl. Each creature within 15 feet of the Umberthane must succeed on a DC 14 Wisdom saving throw or be frightened until the start of the Umberthane's next turn. A creature that succeeds on the saving throw is immune to the effects of this feature for 24 hours.

Multiattack. The Umberthane makes two attacks: one with its bite and one with its shadow lash.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 9 (1d8 + 5) [piercing] damage, plus 3 (1d6) [psychic] damage if the target is in dim light or darkness.

Shadow Lash. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 6 (1d6 + 3) [necrotic] damage. If the target is in dim light or darkness, it must succeed on a DC 14 Constitution saving throw or be restrained by shadows until the end of the Umberthane’s next turn.

Shadow Step. The Umberthane can teleport up to 15 feet to an unoccupied space that it can see. This ability can be used as a bonus action once per turn, but only in dim light or darkness

Evasion. If the Umberthane is subjected to an effect that allows it to make a Dexterity saving throw to take only half damage, the Umberthane instead takes no damage if it succeeds on the saving throw, and only half damage if it fails.