In the Limited Edition ICO and Shadow of the Colossus Box Set for PS3, an art book titled 'Shinwa wo Tsumugu' is included. It features some interviews with members of Team ICO and among them is Junichi Hosono, who claims Ueda derived Yorda's name from the character of Hilda in the Toei film, 'Horus: Prince of the Sun'.

This is somewhat corroborated by the movie's presence on Ueda's shelf, which is shown in this same art book.

Hilda's character traits and arc are very different from that of Yorda, but her dynamic between the valiant Horus and the ice devil Grunwald seemed to serve as a heavy inspiration for ICO's narrative.