Black Uruk-Hai Beastlord

Winter Wolves. The Uruk-Hai Beastlord commands a pack or several packs of Winter Wolf Minions. Each pack of 4 wolves act at the same initiative.

Beast Handler's Immunity The orc has advantage on saving throws against poison and disease.

Mount Master: Winter Wolf. When the Beastlord is mounted on a Winter Wolf, all attacks must target the mount first. To the Beastlord, the wolf is no more than a shield.

Hit 'em while they're down. The Beastlord makes all attacks against prone creatures with advantage.

Multi-attack. The Beastlord makes two Chainflail or two Spiked Gauntlet attacks. 

Chainflail. Ranged Weapon Attack: +6 to hit, range 30/60 ft., 1 target. Hit: 12 (1d10+6) bludgeoning damage, and the target must succeed an Acrobatics or Athletics check against the attack roll or be knocked prone. 

Spiked Gauntlet. Melee Weapon Attack: +6 to hit, reach 5ft., 1 target. Hit: 10 (2d4+6) piercing damage.

Cruel Master. The Beastlord can use one of his attacks to violently lash out at a Winter Wolf Minion, attacking it with his chain. On a successful hit, the wolf wretches a black-blue bile (e.g. liquid hydrogen) in a 10-foot cube. Each creature in that area must make a DC 14 Dexterity saving throw, taking 6 cold damage on a failed save, or half as much damage on a successful one.  The target wolf dies as a result of this action.

Chain Mount. The Beastlord can use his bonus action to pull himself to a Winter Wolf Minion, which he can see within 60ft. 

Command Winter Wolf. The Beastlord can use his bonus action to command a Winter Wolf, to immediately take one of its actions.

Devour Beast Blood. When a Winter Wolf Minion dies within 5ft of the Black Uruk-Hai Beastlord, he can use his reaction to drink the wolf's blood, healing himself for 2d12 hit points.