Avatar form: When Adriel falls to 0 Hit points, she drops her avatar form and enters her true form as an Arch devil. Adriel is replaced by Adriel, The God slayer and champion of the nine hells.

Legendary resistance (3/day): If Adriel fails a saving throw, she can choose to succeed instead.

Magic resistance: Adriel has advantage on saving throws against spells and other magic effects.

Siege monster: Adriel deals double damage to buildings and objects

God slayer: Adriel deals an additional 60 (10d10) necrotic damage when attacking a paladin or cleric

Spellcasting: Adriel's spellcasting ability is Wisdom (spell save DC 26, +18 to hit with spell attacks). Adriel has the following spells prepared:

Cantrips (at will): Light, Message, Minor illusion, Poison spray, Ray of Frost, True strike 

1st level (10 slots): Burning hands, Chromatic orb, Detect Magic, Disguise self, Expeditious  retreat, False life, Feather fall, Identify

2nd level (10 slots): Crown of madness, Detect thoughts, Enlarge/reduce, Hold person, Knock, Scorching ray, Suggestion

3rd level (8 slots): Counterspell, Fireball, Haste, Remove curse, Slow, Vampiric touch

4th level (8 slots): Banishment, Confusion, Dimension door, Greater invisibility, Locate Creature, Stone Shape, Wall of fire

5th level (6 slots): Dominate person, Hold monster, Scrying

Multiattack: Adriel can make five attacks on her turn: three with her axe, one with her bow and cast one spell.

Axe of destruction: Melee weapon attack: +19 to hit, reach 10 ft., one target. Hit: 49 (5d12 + 14) slashing damage. An attack made with this weapon against a structure or object is an automatic critical hit.

Adriel's bow: Ranged Weapon Attack: +16 to hit, range 300/1200 ft., one target. Hit: 67 (7d12 + 18) piercing damage. The target must then make a wisdom saving throw (DC 23) or become frightened of Adriel, this effect lasts for 1 minute. The target can repeat the saving throw at the start of their turn.

Adriel gets three legendary actions per round, choosing from the available options below. She can only use one at a time and can only use them at the end of another players turn.

Attack: Adriel can make one attack with her axe.

Bow shot (Costs 2 actions): Adriel can fire a shot from her bow

Cast spell (costs 2 actions): Adriel can cast one spell from her available spells