Thea is a young woman rescued by Shuna from a slave citadel. She is hard working and sincere and her love for Shuna couldn't be purer. Her background is a little unclear; the slave handler who attempted to sell her to Shuna claimed her to be royalty, which she staunchly denied.

Spoiler

She later finds Shuna after his journey to the land of the god-like ones and helps him plant the golden wheat.

(Source: shuna.ten-trees.net)