Ahkrak, Khal of Ostraxad

Rampage. When the Khal reduces a creature to 0 hit points with a melee attack on its turn, the gnoll can take a bonus action to move up to half its speed and make a bite attack.

Aggressive. As a bonus action, the Khal can move up to its speed toward a hostile creature that it can see.

Multiattack. The Khal makes three attacks: two with his spear, and one with his bite.

Khal's Spear. Melee Weapon Attack: +8 to hit, reach 10 ft., 1 target. Hit: 3d8 + 5 slashing damage. On a hit, the spear lets loose necrotic energy, targeting another enemy of the Khal's choice within 60 feet. The targeted creature must make a Dexterity saving throw. A creature takes 2d8+5 necrotic damage on a failed save, or half as much damage on a successful one.

Baneful Bolt Spell Attack +6 to hit, reach 120 feet, 1 target. Hit: 2d10+2 necrotic damage.

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

Unbridled Fury. In response to being hit by a melee attack, the Khal can make one melee weapon attack with advantage against the attacker.

Hellish Yowl  As a bonus action, the Khal lets loose a blood-curdling yowl. Each non-undead creature within 60 feet of the Khal that can see it must succeed on a DC 16 Wisdom saving throw or be frightened for 1 minute. A frightened target can repeat the saving throw at the end of each of its turns, ending the frightened condition on itself on a success.

Legendary Resistance (3/Day). If the Khal fails a saving throw, it can choose to succeed instead.