Aledraim The Lich King

Lich Kings Fortitude (Recharges after a Short or Long Rest). If Aledraim would be reduced to 0 hit points, his current hit point total instead resets to 200 hit points, and he recharges his Hellfire Ray and Invoke Death Curse. Additionally, Aledraim can now use the options in the "Mythic Actions" section for 1 hour. Award a party an additional 15,000 XP (30,000 XP total) for defeating Aledraim after its Lich Kings Fortitude activates.

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

Spellcasting. Aledraim is a 10th-level spellcaster. his spellcasting ability is Charisma (spell save DC 18, +8 to hit with spell attacks). Aledraim has the following Paladin spells prepared:
1st level (4 slots): Hellish Rebuke, Inflict Wounds, Command, [spell[Compelled Duel[/spell]
2nd level (3 slots): Darkness, Hold Person
3th level (2 slots): Dispel Magic, Aura of Vitality, Fireball (necrotic damage), Counterspell
4th level (2 slots):  Banishment
5th level (1 slot): Destructive Wave (necrotic)

Multi Attack. Aledraim uses Death Tether and then makes 2 greatsword strikes or 1 Vampiric drain.

Greatsword strike. Melee Weapon Attack: +8 to hit, reach 5 ft., 1 target. Hit: 16 (3d6 + 8) Slashing damage. And Necrotic Smite Hit: 8 (2d6 + 2) Necrotic damage

Vampiric drain. Ranged Spell Attack: +8 to hit, range 60 ft, 1 target. Hit: 12 (4d6 +4) Necrotic damage. Drain the life of the enemy healing half of the Necrotic damage dealt.

Death Tether.  Ranged Spell Attack: +8 to hit, range 60 ft., 1 target. Hit: 3 (2d6) Necrotic damage. On a hit the enemy must make a DC 18 Strength saving throw or be pulled 30ft towards Aledraim.

Invoke Death Curse (Recharge 5-6). Ledraim targets one creature he can see within 60 feet of him. The target must succeed on a Constitution saving throw  DC 18 or be cursed. While cursed in this way, the target can’t regain hit points and has vulnerability to necrotic damage. A greater restoration, remove curse, or similar spell ends the curse on the target.

Hellfire Ray (Recharge 6):
Range 60 ft. Aledraim sends negative energy coursing through a creature that he can see within range, causing it searing pain. The target must make a DC 18 Constitution saving throw. It takes 3d8 + 10 necrotic damage and 3d8 + 10 fire damage on a failed save, or half as much damage on a successful one.
A humanoid killed by this spell rises at the start of its next turn as a wight that is permanently under Aledraim command.

Attack of Opportunity. Aledraim can use his reaction to make a melee attack on someone.

Hellish Rebuke. Aledraim can use his reaction to Cast Hellish rebuke on his attacker.

Counterspell. Aledraim can use his reaction to Cast Counterspell.

Parry. Aledraim adds 5 to its AC against one melee attack that would hit it. To do so, Aledraim must see the attacker and be wielding a melee weapon.

Can take 3 Legendary Actions, choosing from the options below. Only one legendary action can be used at a time, and only at the end of another creature's turn. Spent legendary actions are regained at the start of each turn.

Melee attack: Aledraim makes one greatsword attack

Death tether: Aledraim uses death tether

Vampiric drain: Aledraim uses Vampiric drain.

Movement: Aledraim moves 30 feet

Casting a spell (Costs 2 Actions): Aledraim casts a spell of 3rd level or lower

Frightening Gaze (Costs 2 Actions): Aledraim fixes its gaze on one creature it can see within 10 feet of it. The target must succeed on a DC 18 Wisdom saving throw against this magic or become Frightened for 1 minute. The Frightened target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a target's saving throw is successful or the effect ends for it, the target is immune to Ledraim's gaze for the next 24 hours.

Disrupt Life (Costs 3 Actions): Each non-undead creature within 20 feet of Aledraim must make a DC 18 Constitution saving throw against this magic, taking 25 (7d6) necrotic damage on a failed save, or half as much damage on a successful one.

If Aledraim's Lich Kings Fortitude trait has activated in the last hour, he can use the options below as legendary actions.

Consume Life (Costs 3 Actions): Each creature within 20 feet of Aledraim must make a DC 18 Constitution saving throw against this magic, taking 18 (5d6) necrotic damage on a failed save, or half as much damage on a successful one. Aledraim heals half of  the necrotic damage dealt