Aerowen

Unwilling. This creature cannot be banished or sent to another plane of existence by any means.

Divine Technique: Banishment. This creature can use it's action to cast Banishment. DC 17 and if wielding Dragon Bone can also cast it as a level 5 spell. This trait can only be used once per day unless Dragon bone is wielded by Aerowen, then she can us it as many times as Dragon Bone has charges

Divine Technique: Smite. While wielding Dragon Bone, this creature can imbue it's attack with Banishing Smite. This trait has a recharge of 3 turns.

Dragon Bone. Whenever a spell is cast by another creature in range of 30 ft. Dragon Bone gains charge. If 5 or more charges are expended Dragon Bone user can make Dash (no action required) towards its target.

Plane of Divine Flavor. Whenever Aerowen banishes a creature it is sent to her own demiplane which she has control, there all creature are as if under the influence of Dominate Monster, except Aerowen doesn't need to be on the same plane of existence. To break out of this demiplane a creature has to succeed a wisdom saving throw with disadvantage (DC 35) and have a means to travel between planes.

Sheath Strike. Melee Weapon Attack: +10 to hit, reach 5 ft., one target, Hit 19 (2d12 + 6) Bludgeoning Damage.

Dragon Strike. Melee Weapon Attack: +15 to hit, reach 5 ft., one target, Hit 22 (2d12 + 10) Slashing Damage. Charges from Dragon Bone can be used to empower this attack by addition d8 for a charge

This creature can use it's legendary actions only if she wields Dragon Bone. She begins with 3 legendary actions and she doesn't regain actions at the beginning of her turn. She gains a action whenever Dragon Bone is used or if she successfully banishes someone. Legendary actions can only be used during end of another creatures turn.

Sword Strike. Aerowen does dragon strike.

Heartless Heaven Technique: Divine Word (Cost 4 Actions). Aerowen casts Divine Word. DC 20

Divine Technique: Recharge (Costs 2 Actions). Each trait can be used one turn sooner. Dragon Bone gains one charge.

If Aerowen is holding Dragon Bone when she drops to 0 hp, she instead merges with her weapon and becomes her true draconic form. She become an Ancient White Dragon, while her wisdom, intelligence and charisma stats remain the same. She also retains her demiplane and ability to banish creatures. She gains charges as if she was Dragon Bone.