Keen Hearing and Smell. The dog has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Fae Shapechanging. Zermuthu can change forms, size and appearance at will

Fae innate spellcasting. Zermuthu is a 7th level spellcasting using Cha as their spellcasting ability.

Bite. Melee Weapon Attack: [rollable]+5 to hit, reach 5 ft., one target. Hit: 8 [rollable](2d6 + 1) piercing damage.

Teleport [rollable](Recharge 4–6). The dog magically teleports, along with any equipment it is wearing or carrying, up to 40 feet to an unoccupied space it can see. Before or after teleporting, the dog can make one bite attack.