Beast of Infinite Souls

Destroyed Flesh: Every 200 damage the Beast of Infinite Souls first takes, one warped arm is destroyed, revealing a cast of magical energy vaguely resembling an arm and hand.

Strike of Pride: The Beast fails every Dexterity Saving throw it must make, but can roll half the damage dice to reduce damage. If the damage results in a negative, The Beast takes 0 damage.

Spellcasting. The Beast of Infinite Souls is a 9-level spellcaster. Its spellcasting ability is wisdom (spell save DC 18, +8 to hit). The Beast has the following wizard spells prepared:
Cantrips (at will): True Strike, Shocking Grasp                  5th level (6 slots): Cone of Cold, Magic Missile                  7th level (4 slots): Finger of Death,  Eyebite

Domain's Voice: The Beast of Infinite Souls can communicate telepathically with any creature in the Garden in whatever language they desire.

Terrifying Defense: Upon failing to hit the Beast when the Beast has been targeted specifically, the creature attacking must make a wisdom saving throw of 15. If the attacker fails, it becomes frightened.

 Four-Eyes: Eyebite can be performed twice using one action and one spell slot.

Claw: Melee attack. +10 to hit, 20ft. to reach, 1 target. Hit: 42 (8d8+10) slashing damage. Does 4 less damage (One less d8 die) each time one of the Beast's arms are destroyed.

Tendrils of the Beast: Ranged attack. +8 to hit. 100ft. to reach. Up to 6 targets. Hit: 38 (6d8+8) Piercing damage. Each d8 of damage can hit a separate target, but requires another DC roll for each new creature. The +8 damage always hits the first target.

Strike of Greed: This bonus action allows the Beast to perform another attack this turn whether an attack has been made or not, at the cost of not being able to perform a reaction that round. If a reaction has already been used that round Strike of Greed can not be performed.

Infinite Souls: Upon taking damage, the Beast may can make a constitution saving throw of 14. On a success, the Beast can summon souls from the cavity in its chest, healing 50 (8d10+10) health to itself, raising its AC to 20 next time it is hit, or dealing an extra dice of damage with whatever attack it makes next. This reaction can be preformed every other round.

Strike of Gluttony: Upon taking damage, the Beast can consume 1 of its 8 arms, activating destroyed flesh and healing 100 (10d10+50) health. This can be performed twice per long rest.

Strike of Envy: The Beast can perform the attack it was hit with against any target in range, with advantage on DC. No stats are changed from the original attack. This can be performed 2 times per long rest.

Strike of Sloth: This ranged attack can target up to 4 creatures within 100 ft. Requires 2-4 actions to use (Choose upon using the action), where the Beast remains motionless. At the end of the round where the legendary action finishes, the Beast has 2 options. The first is regain health. The Beast regains 75 (10d10+25) health for if 2 actions are used, 100 (12d10+40) health for 3 actions, or 125 (14d10+55) health for 4 actions. The other option is to attack each target with the amount of damage the Beast has taken during this time. Each target can roll a constitution saving throw of 20 to reduce the damage taken by half. This action can be used once per long rest. 

Required Destination: This legendary action requires 1 action. When the Beast is too far away to reach a target, it can approach any length of feet until it is close enough.

Raw Power: Upon losing 1 or more physical arms, the Beast can use raw power. +10 to hit. Melee attack. 20ft. to reach, 1 target. Hit: 70 (10d10+20) Necrotic damage. 30 (6d10) Damage to the Beast.

Strike of Wrath: Upon losing all 8 of its physical arms, the Beast can use Strike of Wrath. +12 to hit. Melee attack. 20ft. to reach, 1 target. Hit: 100 (12d10+30) Necrotic damage. 40 (8d10) Damage to the Beast