Challenger

Danger Mode (1/Battle). "It appears I must take this seriously."

When Challenger drops below 75 hit points, he makes 3 melee attacks instead of 2 and his speed increases to 60 ft. For 3 rounds, he rages, and becomes resistant to piercing, slashing and bludgeoning damage. Add 2 damage to all his melee attacks. He gains four levels of exhaustion at the end of this effect.

Magic Resistance. Challenger has advantage on saving throws against spells and other magical effects.

Superiority Dice. Challenger has five superiority dice, which he can apply to attacks that hit.

Trip: +1d8 bludgeoning and large or smaller targets must succeed DC 15 strength save or be knocked prone.

Disarm: +1d8 bludgeoning and target must succeed DC 15 strength saving throw or have an item they're holding knocked out of their hand. It's dropped up to 10 feet away in a direction of Challenger's choice.

Multiattack. Challenger makes two attacks.

Relic of Iron Gauntlets. Melee Weapon Attack: +8 to hit, reach 5 ft., 1 target. Hit: 13 (2d8 + 4) bludegoning damage. 

Sonic Scream (Recharge 5~6) Challenger forces everyone in a 15 cone Radius to make a 16 CON save or take 27 (8d6) thunder damage. They take half as much on a successful save.

Challenger can take 2 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. Challenger regains spent legendary actions at the start of its turn.

Intimidating Glare (Costs 2 Actions). Challenger forces everyone he chooses who can see him in a 60 ft. radius to make a DC 16 WIS save or become frightened until the end of Challenger's next turn.

Shove. Target within 5 ft. must make DC 15 STR/DEX save or else be pushed up to 5 ft. and be knocked prone.

Move. Challenger moves up to his movement speed.