Xinstal Deathrunner, Breaker of Immortality

Breaker of Immortality (Recharges after a Short or Long Rest). If Xinstal or if Seraph is within 100ft and would drop to 0 hit points , something happens off the following list. (Award an additional 100,000 xp, (Max 200,000) for defeating Xinstal after each stat increase) 

• (If first time meeting/fighting Xinstal). Xinstal laughs maniacally as he dissipates into dust and returns to Seraph Soulstealer's side.
• (If the person/persons has fought Xinstal once before). (Xinstal's CR increases to 27). Xinstal instantly regains 1 hit point and 150 temporary hit points and 1 addition AC, (Decaying temporary hit points by 10 every round until not in combat. If within 100ft of Seraph Soulstealer, does not decay). 
• (If the person/persons has fought Xinstal more than twice). (Xinstal's CR increases to 30). Xinstal instantly regains 1 hit point and 300 temporary hit points and 1 additional AC, (Decaying temporary hit points by 20 every round until not in combat. If within 100ft of Seraph Soulstealer, does not decay). 

Magic Resistance Xinstal has advantage on saving throws against spells and other magical effects.

Marshal Undead Unless Xinstal is incapacitated, it and undead creatures of its choice within 30 feet of it have advantage on saving throws against features that turn undead. Xinstal is also considered Immune to turning magic.

Stagger If the damage Xinstal deals is a quarter of the max health of the target in one attack it is stunned until the Xinstal's next turn.

Immutable Form Xinstal is immune to shape changing magic.

Legendary Resistance (3/Day) If Xinstal fails a saving throw, he can choose to succeed instead.

 Spellcasting Xinstal is a 20th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 20,). It has the following spell prepared:

2nd level (5 slots): misty step

3rd level (5 slots): revivify life transference

4th level (5 slots): banishment find greater steed

5th level (3 slots): raise dead banishing smite

8th level (3 slots): heat metal

9th level (1 slots): power word kill

Multiattack. Xinstal makes three greatsword attacks.

Deathrunner's Greatsword. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit:  19 (2d12 + 6) slashing damage, or 25 (3d12 + 6) slashing damage if used with two hands, plus 27 (6d8) necrotic damage.

Undead Orb (1/Day). Xinstal hurls a magical ball of necrotic jet black that explodes at a point it can see within 120 feet of it. Each creature in a 30-foot-radius sphere centered on that point must make a DC 15 Dexterity saving throw. The sphere spreads around corners.  99 (22d8) necrotic damage on a failed save, or half as much damage on a successful one.

Column Smash. Xinstal makes a DC 17 strength check, (with a strength score requirement of 20), to lift and wield one marble column in one free hand. He can use it as a melee weapon, Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 25 (3d12 + 5) bludgeoning damage, or can throw it if he succeeds a DC 17 dexterity check which then deals, Ranged Weapon Attack: +13 to hit, range 60ft/120ft, one target. Hit: 25 (3d12 + 5) bludgeoning damage. The creature hit makes a strength saving throw of DC 17; if it fails it is moved 30ft away from the thrower in a straight line, the creature does not move if it succeeds. If the creature hits a hard surface within the 30ft, calculate the damage as fall damage.

Parry. Xinstal adds 8 to its AC against one melee attack that would hit it. To do so, Xinstal must see the attacker and be wielding a melee weapon. He then makes a greatsword attack against the target.

 Side Step. Xinstal uses his extremely fast reflexes and side steps a single target ability, mele/ranged attack, or single target spell and takes half damage from said attack.

Xinstal can take 2 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. Xinstal regains spent legendary actions at the start of his next turn.

Fear the Undead (Costs 1 actions). Xinstal lets out an undead howl. All creatures that aren't undead within 30ft of Xinstal must succeed on a DC 20 Wisdom saving throw or be feared of Xinstal for 1 minute.

Undead Smite (Costs 2 actions). Xinstal imbues his sword with deathly power. On his next hit with his greatsword it deals,  32 (5d12) necrotic damage.

If Xinstal's Breaker of Immortality trait has activated in the last hour, he can use the options below as legendary actions. The amount of legendary actions Xinstal can take increases to 3.

Immortal Servent (Costs 1 action, can only be used after damage calculation is done). If Xinstal is within 100ft of Seraph Soulstealer he takes an action to consume the damage done to his master. He takes all damage from the attack instead of Seraph.

Greater Undead Smite (Costs 3 actions). Xinstal gains power from the rage of battle and imbues his sword with part of his being. Xinstal subtracts temporary hit points/hit points and adds them to his next attack. The amount he adds cannot be less than 1 and not more than the amount of current hit points/temporary hit points. This damage is necrotic.