Avatar of Gruumsh

Rallying Presence. Gruumsh exudes a presence that inspires its allies to greater feats. Creatures of its choice within a 120 feet of himself can roll and add a d6 to their attack rolls, saving throws, or ability checks. When they are attacked, they can use their reaction to add a d6 to their armor class. 

Orcs in the area gain an additional action on each of their turns. 

Terrorizing Strike (5/day). When Gruumsh deals damage to a creature with a melee weapon attack, it can force the target to make a DC 27 wisdom saving throw, taking 17 (5d6) psychic damage on a failed save or half as much on a successful one. On a failed save, a creature is also frightened of Gruumsh for an hour.

A creature frightened in this way takes 17 (5d6) psychic damage at the start of each of it's turns. The creature can repeat the save at the end of each of it's turns, ending the effect on a success.

Raging Might (3/day). Gruumsh can unleash its rage in mighty blows. When it deals damage to a creature with a melee weapon attack, it can choose to deal additional damage to the target equal to half the damage it took since it's last round. 

Unstoppable Force. Once Gruumsh starts going, it cannot be stopped. When Gruumsh makes a saving throw, it can gain a +1 bonus to the save for every 20 damage it did on it's last turn.

In addition, its speed cannot be reduce in any way.

Legendary Resistance (5/Day). If Gruumsh fails a saving throw, it can choose to succeed instead.

Limited Magic Immunity. Unless it wishes to be affected, Gruumsh is immune to spells of 4th level or lower that target it or include it in their area of effect. Gruumsh has advantage on saving throws against all other spells and magical effects.

Multiattack. Gruumsh makes 3 attacks with it's greataxe and an attack with it's claw. It cane replace the claw attack with a fling action.

Greataxe. Melee or Ranged Weapon Attack: +19 to hit, reach 15 ft. or range 60/180 ft., one target. Hit: 33 (5d8 + 10) slashing damage. If the greataxe was used it make a melee attack, and the target is medium or smaller, it must make a DC 27 strength saving throw, being knocked prone and taking 9 (2d8) bludgeoning damage on a failed save or taking half as much damage and not being knocked prone on a successful one.

Claw. Melee Weapon Attack: +19 to hit, reach 10 ft., one target. Hit: 27 (3d10 + 10) slashing damage, and the target is grappled (escape DC 27). Until this grapple ends, the target is restrained and the Gruumsh can't grapple another target this way.

Fling. One Large or smaller object held or creature grappled by Gruumsh is thrown up to 120 feet in a random direction and knocked prone. If a thrown target strikes a solid surface, the target takes 4 (1d8) bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 27 Dexterity saving throw or take the same damage and be knocked prone.

Death Haze (Recharge 6). Gruumsh create a cloud of acrid smoke around him that burns through everything it touches. It forms in a 30 foot sphere centered on himself, which is heavily obscured. Gruumsh and any orcs can see through this haze.

The haze lasts for a minute. While it lasts, a creature  other than Gruumsh or an orc who starts it's turn in the haze must make a DC 27 constitution saving throw, taking 54 (12d8) acid damage on a failed save, or half as much on a successful one. 

During each of Gruumish's turns, it can move the haze up to 60 feet in any direction instead of moving.

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

Bear-Down (Recharge 5-6). As a bonus action, Gruumsh can exude his terrifying presence on its enemies. A creature frightened of it takes 17 (5d6) psychic damage. 

Gruumsh can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. Gruumsh regains spent legendary actions at the start of his turn.

Claw. Gruumsh makes a claw attack.  

Teleport (Costs 2 Actions). Gruumsh teleports to a location of it's choice inside of it's death haze, if it has one. 

Summon Army (Costs 3 Actions). Up to 10 orcs appear in locations of Gruumsh's choosing within 200 feet of himself.