Millie

Combat Abilities:

Plane Shift Strike: Millie makes a spell melee attack against a creature. She has a +9 to hit. The creature must then pass a DC 19 CHA save. On a fail they are teleported to a random location on a plane Millie picks. Using this ability again before taking a long rest, swaps the new creature with the already teleported creature.
Otherworldly Summon: Millie summons something at random, aiming at a single target. She rolls a d6 to determine the nature of the summon. 1-5 harms enemy creatures, or heals allied creatures. A 6 heals enemy creatures or harms allied creatures. She must then roll a d20 to determine the severity of the summon.
Quick Thinking: As a reaction to an ally falling unsconscious, Millie can teleport the closest safe location. She always knows where this location is. The creature still rolls death saves, however, rolling above a 15 automatically stabalizes the creature.

Vehicle or Special Ability:

Dream of the Blue Veil: (Once per day). Millie casts a modified version of Dream of the Blue Veil. A D20 must be rolled. Rolling under a 10 has ends the spell and grants a level of exhaustion. Rolling 10-19 ends the spell. On a 20, all creatures cross into another world for six hours. Afterwhich, they wake up, with anything they had on their person.

Travel Ability:

Retreat: Millie uses her magic to escape from difficult situations. If the party rolls a "bad" outcome, they do not suffer the outcome of the travel roll. Instead, they are transported back half the distance they traveled.