Arshoon The Fallen

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

Marshal Undead. Unless Arshoon is incapacitated, it and undead creatures of its choice within 60 feet of it have advantage on saving throws against features that turn undead.

Spellcasting. Arshoon is a 17th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 17, +10 to hit with spell attacks). It has the following paladin spells prepared:

1st level (4 slots): command, compelled duel, searing smite

2nd level (3 slots): hold person, magic weapon

3rd level (3 slots): dispel magic, elemental weapon

4th level (3 slots): banishment, staggering smite

5th level (2 slots): destructive wave (necrotic)

Multiattack. Arshoon makes two longsword attacks.

Death Blade (Longsword). (Cursed) Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 9 (1d8 + 5) slashing damage, or 10 (1d10 + 5) slashing damage if used with two hands, plus 8 (2d8) necrotic damage.

Hellfire Orb (1/Day). Arshoon hurls a magical ball of fire that explodes at a point it can see within 120 feet of it. Each creature in a 20-foot-radius sphere centered on that point must make a DC 17 Dexterity saving throw. The sphere spreads around corners. A creature takes (8d6) fire damage and (8d6) necrotic damage on a failed save, or half as much damage on a successful one.

Parry. Arshoon adds 6 to its AC against one melee attack that would hit it. To do so, the death knight must see the attacker and be wielding a melee weapon.

Arshoon The Fallen has 3 legendary actions per round. Choose from the following actions below. 

Pommel Strike - Arshoon attacked with the butt of his sword causing (1D6+5) damage. The creature then makes a Con saving throw (DC16) or is staggered and can't take reactions that turn. 

Command Creature - Arshoon can command any allied creature to make one weapon attack using its reaction. 

Crippling Fear (2 L/A) - Arshoon looks into a creature's eyes showing them their greatest fear. The effected creature must make a Wis saving throw (DC16) or be stunned. Can repeat the throw at the end of each of its turns. Once passed the creature is immune to this effect for 24hrs.