Greek mythology adapted as anime. It's a pretty logical combination if you think of it. There's a lot of drama, action, fantasy elements and the themes are quite adult. It also helps that Arion is a quality production, so all the ingredients are there to make Arion an epic fantasy anime, and that's exactly what it is.
Arion, the son of Prometheus, is banished to the underworld. He isn't just resigning himself to his fate, and so he starts his journey upwards, back to where he belongs. When he finally escapes Hades' underworld, he finds himself in the middle of a war between gods, giants and humanity.
The film throws a few Greek myths together and constructs an epic journey from them. The animation is lovely, the adventure feels epic and Hisaishi's score is an asset. At two hours, it's probably a bit too long, and the lead character lacks individuality, other than that this was a pretty fun fantasy anime.