Yeth Hound

Yeth Hound CR: 4

Large fey, neutral evil

Armor Class: 14 (natural armour)

Hit Points: 51 6d10+18

Speed: 40 ft , fly: 40 ft , can hover

STR

18 +4

DEX

17 +3

CON

16 +3

INT

5 -3

WIS

12 +1

CHA

7 -2

Damage Immunities: Bludgeoning, Piercing, and Slashing from nonmagical attacks not made with silvered weapons

Condition Immunities: Charmed, exhaustion, frightened

Senses: Darkvision 60 ft, passive Perception 11

Languages: Understands Common, Elvish, and Sylvan but cannot speak.

Challenge Rating: 4

Keen Hearing and Smell. The yeth hound has on Wisdom (Perception) checks that rely on hearing or smell.
Sunlight Banishment. If the yeth hound starts it's turn in sunlight, it is transported to the Ethereal Plane. While sunlight shines on the spot from which it vanished, the hound must remain on the Deep Ethereal. After sunset it returns to the Border Ethereal at the same spot, whereupon it typically sets out to find it's pack or master. The hound is visible on the Material Plane while it is in the Border Ethereal, and vice versa, but it can't affect or be affected by anything on the other plane. Once it is adjacent to it's master or a pack mate that is on the Material Plane, a yeth hound on the Border Ethereal can return to the Material Plane as an action.
Telepathic Bond. While the yeth hound is on the same plane of existence as it's master, it can magically convey what it senses to it's master, and the two can communicate telepathically with each other.

Actions

Bite. Melee Weapon Attack +6 to hit, reach 5 ft, one target. Hit 11 2d6+4 piercing damage, plus 14 4d6 psychic damage if the target is frightened.
Baleful Baying. The yeth hound bays magically. Every enemy within 300 feet of the hound that can hear it must succeed on a DC 13 Wisdom saving throw or be frightened until the end of of the hound's next turn or until the hound is incapacitated. A frightened target that starts it's turn within 30 feet of the hound must use all of it's movement on that turn to get as far from the hound as possible, must finish the move before taking an action, and must take most direct route, even if hazards lie in the way. A target that successfully saves is immune to the baying of all yeth hounds for the next 24 hours.

The yeth hound, or yell hound, is a black dog found in southwestern Britain. It usually appears in the Material Plane as a headless dog, and in the Feywild and such with a head with ugly angry humanoid features. Many say it is the spirit of an unbaptised child, and rambles through woodlands at night making wailing sounds.
Sometimes powerful evil beings are granted at least one of these, especially members of the Unseelie Court, or other dark Fey. They act as hunters for such beings.

Suggested Environments

Wooded areas.