Balhannoth of the Peaks

This balhannoth gains or loses power based on the magical items it has acquired and mental anguish it has caused recently. Its CR ranges from 5-12.

Multiattack.

• CR 5: The balhannoth makes a bite attack and a tentacle attack, or it makes up to two tentacle attacks.
• CR 7: The balhannoth makes a bite attack and two tentacle attacks, or it makes up to three tentacle attacks.
• CR 9: The balhannoth makes a bite attack and two tentacle attacks, or it makes up to four tentacle attacks.
• CR 12: The balhannoth makes a bite attack and three tentacle attacks, or it makes up to five tentacle attacks.

Bite. Melee Weapon Attack

• CR 5: +6 to hit, reach 5 ft., one target. Hit: 20 (3d10 + 3) piercing damage.
• CR 7:  +7 to hit, reach 5 ft., one target. Hit: 20 (3d10 + 3) piercing damage.
• CR 9: +7 to hit, reach 5 ft., one target. Hit: 25 (4d10 + 3) piercing damage..
• CR 12: +8 to hit, reach 5 ft., one target. Hit: 30 (4d10 + 8) piercing damage..

Tentacle.

• CR 5: +6 to hit, reach 10 ft., one target. Hit: 10 (2d6 + 3) bludgeoning damage
• CR 7:  +7 to hit, reach 10 ft., one target. Hit: 10 (2d6 + 3) bludgeoning damage
• CR 9: +7 to hit, reach 15 ft., one target. Hit: 14 (3d6 + 3) bludgeoning damage
• CR 12: +8 to hit, reach 15 ft., one target. Hit: 17 (3d6 + 6) bludgeoning damage

and the target is grappled and is moved up to 5 feet toward the balhannoth. Until this grapple ends, the target is restrained, and the balhannoth can't use this tentacle against other targets. The balhannoth has four tentacles. (CR 9+ five)

• CR 5: escape DC 14
• CR 9: escape DC 15
• CR 12: escape DC 16

Additional actions based on magic items recently acquired, these are no longer in affect if the party recovers the item.

• Bloodmourne Axe: As a bonus action, the balhannoth summons an Animated Bloodmourne Axe. The axe fights autonomously and attempts to defend the balhannoth completely.
• Sword of wounding: When an attack hits a target they gain a wound. At the start of each of the wounded creature’s turns, it takes 1d4 necrotic damage for each time you’ve wounded it, and it can then make a DC 15 Constitution saving throw, ending the effect of all such wounds on itself on a success.
• Studded leather armor + 1: The balhannoth gains +1 to its AC
• Elemental Gem of air: The balhannoth can use its action to summon an air as if it had cast the Conjure Elemental spell, no concentration required.
• Power gem: The balhannoth gains +1 to hit with all attacks and spells
• Wizard's spell book: The balhannoth gets the ability to cast any spells in the spell book of the wizard without components using hit bonuses and save DC according to its melee attack scaling.
• Aearee-Quor Sky Ward Cloak: Can levitate at will, gains +1 to to AC and all saving throws.
• Javelin of Lightning: Instead of a bite attack, the balhannoth can target one creature with a bolt of lightning. +7 to hit, range 60 ft., one target. Hit: 17 (5d6) lightning damage.

For each item that the balhannoth possesses its internal CR increases by 1 from 5 to a max of 12. For each mental anguish the balhannoth has caused in the past month, after the item CR has been calculated,  its internal CR increases by 1 from 5 up to a max of 8.

For each level over 5, or for each mental anguish the balhannoth causes not included in its CR, the balhannoth gains 9 (1d10 + 4) health.

LEGENDARY ACTIONS The balhannoth can take (CR5 one, CR7, two, CR9+ three) legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. The balhannoth regains spent legendary actions at the start of its turn.

• Bite Attack. The balhannoth makes one bite attack against one creature it has grappled.
• Teleport. The balhannoth magically teleports, along with any equipment it is wearing or carrying and any creatures it has grappled, up to 60 feet to an unoccupied space it can see.
• Vanish. The balhannoth magically becomes invisible for up to 10 minutes or until immediately after it makes an attack roll.
• Cast spell:The balhannoth casts a cantrip it has access to from a spell book or uses two legendary actions to cast a higher level spell.