Becter

Aura of Chaos. When a creature starts its turn within 20 ft. of Becter, the person controlling Becter's stat sheet rolls a d8 to determine which type of elemental damage the creature will be subjugated to (1/Force, 2/Radiant, 3/Acid, 4/Fire, 5/Cold, 6/Lightning, 7/Thunder, 8/Necrotic). Then the creature must succeed on a DC 24 Dexterity Saving Throw, taking 30 (10d6) on a failure or half as much on a success.

Divine Spellcaster. Becter knows all spells from 0-9th Level, regardless of class or components required, & he may cast all spells at will, no spell slots required. Once per minute in combat, Becter can cast any & all ritual spells with a casting time of 1 minute or more as if they were an action instead. Any range that a spell requires is triple the distance cast from Becter.

Legendary Resistance (5/day). If Becter fails a saving throw, he can choose to succeed instead.

Limited Magic Immunity. Unless Becter wishes to be affected, he is immune to spells of 6th level or lower and has advantage on savings throws of all spells and magical effects

Regeneration. Becter regains 50 Hit Points at the start of his turn.

Multiattack (Recharge 5-6). Becter can make three melee attacks with his Staff of the Magi, each one charged with a 4th level or lower spell. The spell charge ends once all the attacks have been made.

Hellfire Pillar (Recharge 6). Becter chooses a point on the ground that he can see within 480 feet of him. A cylinder of hellfire, 100 feet tall with a 20-foot radius, rises from that point and lasts for 1 minute. Creatures in the area when the pillar erupts, or that end their turn in the area, lose their immunity or resistance to fire damage, or gain vulnerability to fire damage if they did not have any resistance or immunity, for 1 minute. In addition, each creature must make a DC 26 Dexterity saving throw, taking 210 (20d20) fire damage on a failure, or half as much damage on a success.

Staff of the Magi. Melee Weapon Attack: +16 to hit, reach 15 ft., one target. Hit: 3 (1d6) or 4 (1d8) versatile plus Spell Charge effects of the controllers choice.

Summon Devil (2/short rest). Becter magically summons (100% chance of success) one of the following type of devils: 2d4+2 bone devils, 1d6+2 horned devils, 1d6+2 erinyes, 1d4+2 ice devils, or 1d4 pit fiends; or (75% chance of success) one of his Dukes; or (25% chance of success) one archduke.

Elemental Affinity. As a Bonus Action, Becter can change any elemental damage type to any of the ones listed in the Aura of Chaos Trait.

Spellcasting. As a Bonus Action, Becter can cast a spell with a casting time of one action as a Bonus Action instead.

Archduke's Dissonance (Recharge 5-6). Becter attempts to twist the mind of an assailant with disturbing, intrusive thoughts and images. The target must succeed on a DC 25 Wisdom Saving Throw. On a failure, they are goaded to attack an illusory visage of Becter, taking 39 (6d12) Psychic damage.

Spellcasting. Becter can cast a spell with a casting time of 1 Action or Bonus Action as a Reaction.

Becter can take 5 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. If Becter has unspent legendary actions at the end of the round, he may spend and immediately use his remaining legendary actions. Becter regains spent legendary actions at the start of his turn.

Spellcasting (Cost 1 Action). Becter chooses a spell of 4th level or lower & casts it, regardless of casting time.

Maddening Aura (Cost 2 Actions). Becter chooses a point he can see within range, up to 480 ft. Every creature within a 100 ft. cylinder of the area must succeed on a DC 25 Charisma Saving Throw or be subject to the effect of the spell Crown of Madness. Becter can command all creatures under the effect of the spell as an Action on his next turn. 

Cast from Hell (Cost 3 Actions). Becter chooses up to 5 other creatures within a 480 ft. radius. All creatures chosen this way must succeed on a DC 25 Charisma Saving Throw or be subject to the effects of the Banishment spell.

Oblivion Spear (Cost 4 Actions). Becter unleashes a spear of energy & throws it in a line 30 ft. wide & 200 ft. long. Each creature in this line (minus the last creature at the furthest point) must make a DC 25 Dexterity Saving Throw or take 40 (8d10) force damage, half on a success. All creatures within a 100 ft. radius of the furthest point must make the same Saving Throw. On a failure, they are subject to 90 (15d12) force damage, half on a success. Any creature that takes damage from this attack must succeed on a DC 25 Constitution Saving Throw at the start of each of their turns. On a failure, the creature is subject to 32 (8d8) necrotic damage. If a creature fails 3 times in a row, mortal creatures are treated as though they have less than 100HP and are subject to the Disintegrate spell, no save. Should a creature succeed on any of the Constitution Saving Throws beforehand, the effect ends.

Ascendant Form- True Terror (Cost 5 Actions/Recharge 6). Drawing on all aspects of his heritage and various sources of power, Becter becomes more than anyone can imagine. Temporarily he disappears from this reality for the remaining round of combat and re-emerges on initiative count 30 of the next round, disregarding initiative counts. On his emergence, all creatures of Becter's choice in the Nine Hell's are subject to a DC 30 Wisdom save, on a 1 any mortal creature makes they are erased from existence.  On a 2-5 any creature is subjected to madness, 3 levels of exhaustion and takes a permanent -5 to Intelligence, Wisdom and Charisma as well as 240 (24d20) psychic. On a 6-10 any creature is subjected to 1 level of exhaustion and 120 (20d12) psychic damage. On an 11-19 the creature is subject to the Blinded, and Frightened conditions and must look for any exit from the Nine Hell's if possible, even attacking allies to do so, at the end of subsequent turns they may roll a DC 30 Wisdom save, on a success the effect is ended and they become immune to these specific effects. On a 20-24 the creature falls to their knees in Becter's presence to worship him, during each of their subsequent turns they may roll a DC 30 Wisdom saving throw, on a success the effects end and they become immune to these specific effects. On a 25- 29 the creature becomes immobile as reality warps around them locking them in place for 1 full round of combat. 

When this Legendary action is used Becter gains 500 temporary hit points one time only. Further, he is granted the ability to warp space and time as he sees fit within his domain for 1 minute of combat.

In place of his spellcasting he may attempt to subject one creature within the Nine Hell to any point in time or space limited to his imagination. Conversely he can undo any events within the allotted minute or restructure anything as he sees fit. Any living or divine creature subjected to this specific ability must succeed on a DC 30 Constitution save, on a pass they are immune for 1 minute.

Becter has one Mythic Action point, & can only use his Mythic Action while in Ascendant Form, and only once a day. He can choose to expend the Mythic Action point at the end of another creatures turn.

Consolidation of Power (Cost One Action). Becter attempts to syphon all magic power from any entities within 120 ft. radius, centered on himself, followed by their lifeforce. Any creature within the radius must succeed on a DC 30 Intelligence Saving Throw, losing all unspent spell slots on a failure, or half, rounded down, for each level with spell slots remaining. In addition to this effect, for every spell slot stolen, Becter's magical spell attacks deal an additional 10 damage. Further, any creatures who failed the first saving throw must then succeed on a DC 30 Constitution Saving Throw. On a failure, the creature's Hit Point Maximum is reduced to one. For every Hit Point stolen this way, Becter gains Temporary Hit Points by the amount taken.