Siege Monster. The wretch king deals double damage to objects and structures.

Legendary Resistance (2/Day). If the wretch king fails a saving throw, it can choose to succeed instead.

Bound Life. If the gem imbedded it the wretch king`s head is removed or destroyed, the wretch king dies immediately. 

Multiattack. The wretch king makes four attacks: one with its bite, one with its horn crest, and two with its claws.

Bite. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit. 33 (4d12 + 9) piercing damage. If the target is a creature it is grappled (escape DC 19). Until the grapple ends, the target is restrained, and the wretch king cannot bite another target.

Horn Crest. Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 34 (5d10 + 9) piercing damage. 

Claw. Melee Weapon Attack: +17 to hit, reach 15 ft., one target. Hit: 27 (4d8 + 9) slashing damage. 

Necrotic Breath (Recharge 5-6).  The wretch king exhales a blast of dark energy in a 90-foot cone. Each creature in that are must make a DC 27 constitution saving throw taking 78 (13d12) necrotic on a failed save and half as much on a successful one.

The wretch king can take 3 legendary actions, choosing from the options below. Only one action can be used at a time and only when the wretch takes damage more than once from one creature.

Breath Weapon. The wretch king uses its necrotic breath.

Charge(Costs 2 Actions). The wretch king can move up to half its speed and use a horn crest attack.

Retaliate. The wretch king can make two claw attacks or a bite attack.