Thetis

is Queen Elizabeth's personal magician and the best one currently serving the Kingdom of Liones.

Chaos in Liones arc
Thetis remains inside the castle as the battle against Arthur Pendragon takes place, laughing as she feels Lancelot fight.

On the night after the battle, Lancelot tells Thetis that she is weird for praying for the deceased Galand and Melascula who killed thirteen people, to which Thetis replies that she only feels sorry for them and that it was twelve people. Thetis reprimands him for allowing Jericho to kill the prisoner who was their only foothold to get to Camelot, to which Lancelot excuses himself by saying that he could not lift the magical restraint Thetis placed on the prisoner. As Lancelot say that she does not understand how he feels and calls her an old hag, Thetis reminds him that they have the same age and that he does not understand her feelings neither, since reading minds and understanding feelings are two very different things. Tethis leaves telling Lancelot to cool his head with a night breeze.

Current arc
Thetis was present during the audience between Percival's group and the king. She introduces Elizabeth as the queen of Liones and gets annoyed by Meliodas's actions.

She then participates in the meeting in the war room to discuss the situation with Camelot. Thetis reprimends some of the attendants for being noisy and urges Meliodas to get started. When Anghalhad ask why are they fighting a kingdom that was destroyed 16 years ago, Thetis explains that Camelot was recreated in an alternate dimension by the power of Chaos but are now starting this war because there is a price to pay in order to rebuilt and maintain the new Camelot. To further expone her words, she uses her magic to show everyone a vision.

Abilities/Equipment
Thetis is a very skilled magician, enough to be appointed as the queen's personal one.
 * High-level teleportation magic that allows Thetis to appear and disappear at precise locations and teleport groups of people instantaneously.

Weapons

 * Staff

Lancelot
Thetis and Lancelot seem to know each other for some time.