In that movie, Odin is not a hero, but his villainy was not explicit. He is just a god of a rival religion, so, his priest is a rival of Athena. So, he is a rival of Athena because he is the major god in the norse religion, and Athena is from a greek religion.
In the anime series, Asgard was remade, and Odin became a neutral god, that only wants protect Asgard, but, Athena is not his enemy during all the series. Poseidon is his the second main enemy of Odin, because he tried always conquer Asgard, that is near his Empire's entrance.
When Hilda become a Poseidon servant, how Hilda attacks Athena empire, Athena goes stops she, and because this, Odin helped Seiya to destroy the Hilda brainwash with his Sword. Thus, Odin choose Seiya to use the Odin God Robe.
In Soul of Gold, Odin, to combats his archenemy (Loki), uses the Athena Saints and revive they to cheat and defeat Loki. He in all the story, cheats Loki, and Loki gets angry. Odin possess Lyfia and explain about his scheme. But, After Aiolia (choosed by him to uses his God Robe) fail in the fight against Loki, Odin's power could not help anymore.