Vow Rend. Anytime a vow, bet, or pact is made, then broken without fulfillment of the conditions, A'bartheron appears. 

Vow of Life. A'bartheron has taken a vow to avenge those broken. As such, he will stays alive as long as there is a vow that has been broken and unavenged.

Silver Sweep of the Vengeful. Melee Weapon Attack: +10 to hit, reach 15ft., up to 5 targets. Hit: 20(3d#12 + 2) [Slashing] damage. 

Axe Throw. RangedWeapon Attack: +10 to hit, range 120ft., one target. Hit: 30(4d12 + 6) [piercing] damage.

Void Rend. RangedWeapon Attack: +10 to hit, range, all in sight, one target. Hit: 50(8d12 + 2)

Vow of Mending. After A'bartheron has less than half his health remaining, his Vow of Mending activates heals him of all his damage. 

A'bartheron can take up to 4 legendary actions. Legendary action can only be used at the end of a creatures turn. Legendary action that have been used can only be used once per combat.

Vow of Rebirth. If any creature dies, A'bartheron can use his Vow of Rebirth to bring them back to life, including himself.

Vow of Death. If any creature is under 75 hit points, A'bartheron can use his Vow of Death to instantly kill that creature. 

Vow of Aura. A'bartheron can use his Vow of Aura to project one of the following choices of aura. Menacing aura, which gives creatures attacking him disadvantage, Bountiful Aura, which gives allied creatures gain +2 to all rolls, or Disdainful Aura, which give A'bartheron +5 to all rolls. 

Vow of Binding. A'bartheron can make a contract that any creature can agree to. If the creature agrees to the contract, they can take it willingly, if the creature is unwilling, then A'bartheron can try to force it on them and the creature must make a wisdom saving throw.