Unyielding In Death - Once the Death Knight is slain in human form, After 3 minutes a pulse of pure evil will come from it's chest, twisting and mangling the body as the armor forces the body to stand up again.
The Knight get's 1/4 of it's health back, and the Dark aura Hardens the weak Joints in it's armor raising it's AC up by 4.
No one lives - Upon being Slayed in it's Unyielding state, The creature starts to bloat and explodes in a 10 foot Radius. ((Everything the Knight had is destroyed))
Damage - 2d8 + 5 Necrotic Damage.
Dexterity Saving throw - 15.
Dark vision- Able to see up to 60 feet in Magical and Non-magical Darkness.
Action Melee Attack. Slash: +3 to hit, reach 5 ft., 1 target. Hit: 2 (3d6 + 10) Necrotic damage.
Reaction Name.
Shield Master: If you are subjected to an effect that allows you to make a Dexterity saving throw to take only half damage, you can use your reaction to take no damage, if you succeed on the saving throw, interposing your shield between yourself and the source of the effect.
Mage Slayer: When a creature within 5 feet of your casts a spell, you can use your reaction to make a melee attack against the creature.
Description
The Knight is a hulking 8 feet Monster, Wielding a Serrated Black Sword in one hand and a Kite Shield in the other. The Knight is Covered in Plate Mail that has a Wine color to it. In the opening where it's face should be it is covered in darkness, Only a red glow appears where it's eyes should be.
This Knight is from the Blood Lord of the North, The armor is the banners color and the Crest is barred on the shield.
Lair and Lair Actions
As the party open the double doors they unveil a single Knight in the middle of the big room. The knight sits there, Unmoving, undisturbed. Behind the Knight(About 30 feet.) The Sword of the Last King is sheathed in stone, surrounded by a Holy Light.
Once the Party Enters the room the Doors slam shut and cannot be opened, then the knight Stirs from where it is sitting in the room and draws it's weapon and bears it shield, Speaking Infernal the Knight will say,
"Many False Kings have come and non of them alive, I will let Non Rule the land the dead shall rule this world, For the Blood Lord of the North!"
If no one speaks Infernal all they will hear is whispering around the room.