Warlock of the White Dragon

Tiamat’s Dark Blessing. When you reduce a creature to 0 hit points, you gain temporary hit points equal to your Charisma Modifier + your warlock level. If this creature was an ally, you gain double the amount of temporary hit points.

Fiendish Vitality. Tiamat has imbued the warlock with incredible constitution. Gain 2 hit points per warlock level. 

Spellcasting. The Warlock is a 9th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 14, +6 to hit with spell attacks). The mage has the following warlock spells prepared:

Cantrips (at will): eldritch blast, minor illusion, mage hand, prestidigitation

1st level (1 slot/Short Rest): arms of hadar, armor of agathys

2nd level (1 slot/Short Rest): crown of madness, suggestion

3rd level (2 slots/Day): counterspell, fireball, bestow curse

4th level (3 slots/Day): banishment, ice storm

5th level (1 slot/Day): infernal calling

Dagger. Melee or Ranged Weapon Attack: +5 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 4 (1d4 + 2) piercing damage.

Legendary Resistance (1/Day). Donning the White Dragon mask allows you the ability Legendary Resistance. If you fail a saving throw, you can choose to succeed instead.

Herald of the Dragon Queen. Upon entering combat, you sacrifice two ally minions to the Serpent Statue. The Statue’s power awakens the two Serpentine Gargoyle’s. During the first round of combat, you are empowered and your Charisma bonus is Doubled.

Cull The Weak. On Round 2 of combat and at initiative count 20, you may take a free attack action against the nearest ally minion.

Tiamat's Maw. On round 3 of combat, and at initiative count 20, you sacrifice one more ally minion to the Statue. The statue casts the hallow centered on itself. It uses the effect Vulnerability from it's list of effects. This vulnerability applies to all damage type.