Who plays Thetis in Clash of the Titans?

Thetis is played by Maggie Smith.

What are Thetis's abilities?

Thetis's abilities include water manipulation, cursing, divine magic.

Thetis has 4 mapped relationships in Clash of the Titans. Explore the interactive relationship map for details.

Achilles (Child). Doris (Mother). Nereus (Father). Neptune (Spouse). Peleus (Spouse).

Sea goddess and mother of Calibos, seeks vengeance against Perseus.

Thetis — Family Mother — Calibos (Neil McCarthy)
Thetis is Calibos's fiercely protective mother.

Calibos is explicitly described as the son of Thetis, who seeks vengeance after his transformation.
Thetis — Conflict Vengeful Adversary — Perseus (Harry Hamlin)
Thetis manipulates events against Perseus and his future bride.

Thetis transports Perseus to Joppa and seeks revenge for Calibos, later demanding that Andromeda be sacrificed.
Thetis — Conflict Divine Rival — Zeus (Laurence Olivier)
Their opposing divine decisions shape the mortal conflict.

Thetis acts against Perseus, while Zeus intervenes to equip and restore him and ultimately forbids further vengeance.
Thetis — Conflict Punitive Adversary — Cassiopeia (Siân Phillips)
Cassiopeia's boast provokes Thetis's punishment.

After Cassiopeia claims that Andromeda is more beautiful than Thetis, Thetis declares that Cassiopeia will pay for the boast.

Related entry on Wikidata (Q184437), public domain (CC0).