Cole the Stalwart

Lord of Purity. Cole is unaffected by power word kill, power word stun and power word pain. Furthermore his body can not be destroyed via magical means. 

Legendary resistance (4/ day). Cole can choose to succeed a save if he fails. 

Stalwart resilience (First phase). Bolstered by his own headstrong nature and Briphion's magic, Cole has advantage against being charmed, paralyzed, incapacitated and restrained. 

Crusher (First phase). When making attacks with his stone cane, Cole can force a dc 14 constitution save once per struck creature a turn. Failure causes creatures to be stunned until the end of their next turn. 

Arcane surge (Second phase). Cole's attacks become magical. 

Arcane resilience (Second phase). Cole has advantage against all magical effects. Furthermore, Cole loses his weakness to thunder damage. 

Soulstealer's boon (Second phase). In phase two, all damage Cole deals will regenerate his health by 1/4th of the damage delt. 

Cole makes two attacks of his choice during his turn. 

Jab. Cole makes two jab attacks with his weapon (+10-14 to hit x2, 2d6+8 bludgeoning/magical slashing). (First phase) Creatures hit with this attack receive an extra 1d6 damage per hit if they are stunned. (Second phase). Creatures hit with this attack receive a 1d6 penalty to their next magical weapon or spell attack. 

Slam (First phase). Cole makes a singular downwards smash with his cane (+12 to hit, 3d8+8 bludgeoning). Creatures that are launched into the air with Arcane Horns are attacked with advantage. 

Rend (Second Phase). Cole becomes incorporeal, rushing forwards in a 20ft line. Creatures caught in the path of of this attack make a DC 18 athletics or acrobatics check to avoid damage, receiving only half on a successful save (2d6+10). 

Arcane Horns. Cole braces himself, horns of golden energy protruding from his shoulder. Cole charges a creature, forcing a dexterity save (DC18). Upon failing the creature takes 3d6+8 radiant damage, then must make a constitution saving throw (DC18) to prevent being thrown into the air. If struck to the ground with Slam, the creature takes 3d4 bludgeoning damage from the fall. 

Arcane tail. Cole sweeps a draconic tail of radiant energy in front of himself within a 10ft cone (+12 to hit, 2d6+6 radiant). Creatures struck with this attack make a strength save (DC 16) or are knocked prone. 

Kick. Cole attempts to slam an armoured boot into a target within 5ft (+10 to hit). Upon succeeding, Cole deals 2d4 bludgeoning damage, winding the target creature if they fail a Constitution saving throw (DC20). Winded creatures make their next attack at disadvantage. On a critical hit, Cole knocks the creature prone instead. 

Stomp. Cole attempts to slam his boot down on a creature's foot within 5ft, forcing a dexterity saving throw (DC19). Creatures that fail have their movement halved until the end of their next turn. 

Headbutt. Cole tries to grapple a target within 5ft, forcing them to make an athletics or acrobatics check (DC 18). Upon failure the creature struck with this attack suffers a minor concussion, receiving a 1d6 penalty to their next saving throw or check. 

Human shield. When Cole is targeted by a range attack and there is a creature within 5ft, Cole forces a contested strength check. If the creature fails they are momentarily grappled and dragged between Cole and the attack, increasing his AC by 2. If the attack manages to hit Cole he takes 1/2 of the damage. If the attack misses Cole, the grappled creature takes 1/2 of the damage. After this effect ends Cole pushes the target creature 5ft away from himself. 

Pure Lord's Parry. Cole prepares himself against a melee attack, increasing his AC by 3. If the attack misses Cole parries the attack and grabs the creature by the neck upon failing a dexterity save (DC 18). When grappled this way Cole throws the creature 10ft in a direction of his choice. If targeting another creature with the grappled creature, that creature must make a constitution saving throw (DC 18) or be knocked prone. If the targeted creature rolls a 20 on the die, they catch the thrown creature and prevent them from falling. 

This creature has four legendary actions per initiative count. 

Quickstep (1 action). Cole lunges in a direction of his choice, unable to provoke opportunity attacks as he moves up to 15ft. 

Quick strikes (2 actions). Cole makes a jab attack. 

Wings of purity (2 actions). Cole beats angelic wings of radiant energy, creating a powerful gust of wind in a 10ft radius. Creatures caught in the windstorm make a constitution saving throw (DC18) to prevent themselves from being knocked prone. 

Weave collapse (4 actions). Cole raises his hand, collapsing the weave within the vicinity for approximately six seconds, destabilizing all magical effects and prolonged spells. This effect only comes into effect when Cole believes there is no other option. 

Cole regains his mythic actions on a 5-6 on a 1d6. He can only choose one ability to regain per success. 

Debilitating drain. Once Cole reaches 0 hit points for the first time, his contingency plan springs into motion. Cole's arcane ring drains Briphion's life force and arcane power, bringing him back to full health. The triggering of this ability allows Cole to access his other mythic actions. 

Maelstrom (Recharges on a 5-6). Cole jumps 10ft into the air, selecting a target. The target will be assaulted with a maelstrom of magical blades as Cole blinks to their location, dealing 1d8 magical slashing per hit (+14 to hit, x10). At the end of this Cole presumes a defensive position, bracing himself. Until Cole's next turn, he can use a reaction to cause an explosion of magical slashes to wrap around his body within a 10ft radius, causing 8d6 magical slashing damage on a failed dexterity save to all nearby creatures (DC18).

Arcane lockdown (Recharges on a 4-6).  Cole jams his sword into the ground, an explosion of radiant energy pulsing outwards in a 25ft radius. Creatures caught in the wave of energy take 2d6+6 radiant damage if they fail a wisdom save (DC17). Creatures that fail the saving throw make spell attack rolls at disadvantage until the next initiative count.