Very interesting theory. The Allagan Warrior that could've imprisoned Odin could have been the Phlegethon (the final boss of Crystal Tower: Labyrinth of the Ancients) before he was experimented upon. NOAH Reports detail this: "Imperial annals paint him as a murderous villain, but the writings of the commonfolk reveal Phlegethon's status as a hero of the people."

The CT dates back a few thousands years, we know this because the Allagan Empire was destroyed thousands of years prior, before the order of Magi (those responsible for the Void Ark). So even though he was a part of the Empire before turning against Xande's corrupt rule before being experimented on he could've 'stopped' Odin.