Bastien, the Lizard Wizard

Self-Resurrection. If Bastien dies, even if his body is completely destroyed, he can cast True Resurrection on himself from the afterlife and reappear on any plane of existence he chooses. 

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

Spellcasting. Bastien is an 18th-level spellcaster. His spellcasting ability is Intelligence (spell save DC 17, +9 to hit with spell attacks). The Bastien can cast disguise self and invisibility at will and has the following wizard spells prepared:

Cantrips (at will): fire bolt, light, mage hand, prestidigitation, shocking grasp

1st level (4 slots): detect magic, identify, mage armor*, magic missile

2nd level (3 slots): detect thoughts, mirror image, misty step

3rd level (3 slots): counterspell, fly, lightning bolt

4th level (3 slots): banishment, fire shield, stoneskin*

5th level (3 slots): cone of cold, scrying, wall of force

6th level (1 slot): globe of invulnerability

7th level (1 slot): teleport

8th level (1 slot): mind blank*

9th level (1 slot): time stop

*Bastien casts these spells on himself before combat.

Healing Boop (3/Day). Bastien touches another creature. The target magically regains 20 (4d8 + 2) hit points and is freed from any curse, disease, poison, blindness, or deafness.

Change Shape. Bastien magically polymorphs into a humanoid or beast that has a challenge rating equal to or less than his own, or back into his true form. He reverts to his true form if he dies. Any equipment he is wearing or carrying is absorbed or borne by the new form (Bastien's choice).

In a new form, Bastien retains his game statistics and ability to speak, but his AC, movement modes, Strength, Dexterity, and special senses are replaced by those of the new form, and he gains any statistics and capabilities (except class features, legendary actions, and lair actions) that the new form has but that he lacks.