Thi is one of the protagonists of Super Aleste.
Thi is a intelligent alien lifeform which had been absorbed by the Sphere. When the Sphere attacks Earth, a group of Aleste fighters is sent to destroy it but they are all shot down. However, one of the pilots, Raz, manages to hit the Sphere, enough to allow Thi to escape from her prison.
Thi uses her ESP powers to merge with Raz's Aleste fighter, restoring it and giving it new weapons. By reading his mind she assumes the form of a human girl and urges him to help her liberate the planets under the Sphere's influence in order to weaken it. After the Sphere's core is defeated Thi separates from the ship and floats into the Sphere, interacting with it to liberate all of the lifeforms which were trapped on it's inside. Having completed her mission, she decides to stay on Earth with Raz.