Cain is a 20th-level Wizard. His spellcasting ability is Intelligence (spell save DC 18, +10 to hit with spell attacks). Cain has the following wizard spells prepared:

At will: mage hand, prestidigitation, ray of frost, toll the dead, minor illusion, shield, shatter, create nightfall array(ritual)

1/day: control weather/curse the reader, time stop, curse of ravenous hunger

2/day: teleport/containment, flesh to stone/chain lightning

3/day: negative energy flood/geas/wall of force, sickening radiance/ice storm/blight, counterspell/fireball/hypnotic pattern/vampiric touch, rime's binding ice/flaming sphere/line of fangs/erratic blink, cause fear/burning hands/silvery barbs/fog cloud/ice knife/healing bonfire

Shapechanger. If Cain isn’t in running water or sunlight, he can use his action to polymorph into a Tiny bat, a Medium wolf, or a Medium cloud of mist, or back into his true form. While in bat or wolf form, Cain can’t speak. In bat form, his walking speed is 5 feet, and he has a flying speed of 30 feet. In wolf form, his walking speed is 40 feet. His statistics, other than his size and speed, are unchanged. Anything he is wearing transforms with him, but nothing he is carrying does. He reverts to his true form if he dies. While in mist form, Cain can’t take any actions, speak, or manipulate objects. He is weightless, has a flying speed of 30 feet, can hover, and can enter a hostile creature’s space and stop there. In addition, if air can pass through a space, the mist can do so without squeezing, and he can’t pass through water. He has advantage on Strength, Dexterity, and Constitution saving throws, and it is immune to all nonmagical damage, except the damage he takes from sunlight.   Legendary Resistance (3/Day). If Cain fails a saving throw, he can choose to succeed instead.   Misty Escape. When he drops to 0 hit points outside his coffin, Cain transforms into a cloud of mist (as in the Shapechanger trait) instead of falling unconscious, provided that he isn’t in running water or sunlight. If he can’t transform, he is destroyed. While he has 0 hit points in mist form, he can’t revert to his vampire form, and he must reach his coffin within 2 hours or be destroyed. Once in his coffin, he reverts to his vampire form. He is then paralyzed until he regains at least 1 hit point. After spending 1 hour in his coffin with 0 hit points, he regains 1 hit point.   Regeneration. Cain regains 20 hit points at the start of his turn if he has at least 1 hit point and isn’t in running water or sunlight. If he takes radiant damage or damage from holy water, this trait doesn’t function at the start of his next turn.   Spider Climb. Cain can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.   Vampire Weaknesses. Cain has the following flaws.

• Forbiddance: He can’t enter a residence without an invitation from one of the occupants.
• Harmed by Running Water: He takes 20 acid damage if he ends his turn in running water.
• Stake to the Heart: If a piercing weapon made of wood is driven into his heart while he is incapacitated in his coffin, he is paralyzed until the stake is removed.
• Sunlight Hypersensitivity: While in sunlight, Cain takes 20 radiant damage at the start of his turn, and he has disadvantage on attack rolls and ability checks.
• Wild Rose: If a wild rose flower is placed on his coffin while he is inside, Cain cannot escape.

  Arcane Recovery. Once per day when Cain finishes a short rest, he can choose expended spell slots to recover. The spell slots can have a combined level that is equal to or less than 10, and none of the slots can be 6th level or higher.   Spell Secrets. When Cain casts a spell with a spell slot and the spell deals acid, cold, fire, force, lightning, necrotic, radiant, or thunder damage, he can substitute that damage type with one other type from that list (he can change only one damage type per casting of a spell). He replaces one energy type for another by altering the spell's formula as you cast it. When he casts a spell with a spell slot and the spell requires a saving throw, he can change the saving throw from one ability score to another of his choice. Once he changes a saving throw in this way, he can't do so again until he finish a short or long rest.   Alchemical Casting. When Cain casts a spell with a spell slot, he can expend one additional spell slot to augment its effects for this casting, mixing the raw stuff of magic into his spell to amplify it. The effect depends on the spell slot he expends.

• An additional 1st-level spell slot can increase the spell's raw force. If he rolls damage for the spell when he cast it, increase the damage against every target by 2d10 force damage. If the spell can deal damage on more than one turn, it deals this extra force damage only on the turn he casts the spell.
• An additional 2nd-level spell slot can increase the spell's range. If the spell's range is at least 30 feet, it becomes 1 mile.
• An additional 3rd-level spell slot can increase the spell's potency. Increase the spell's save DC by 2.

  Master of Magic. As a bonus action, Cain can call to mind the ability to cast one spell of his choice from any class's spell list. The spell must be of a level for which you have spell slots, you mustn't have it prepared, and he follows the normal rules for casting it, including expending a spell slot. If the spell isn't a wizard spell, it counts as a wizard spell when he castc it. The ability to cast the spell vanishes from his mind when he casts it or when the current turn ends. He can't use this feature again until he finishes a long rest.   Relentless Nature. If Cain is below half your hit point maximum at the start of your turn, he regains 1D4 hit points. Additonally, if Cain dies, he returns to life 24 hours after death. If his body is destroyed, he reforms within 1 mile of the place of his death at a spot determined by the DM. If his equipment was also destroyed, he does not regain it.