Quote Originally Posted by Enkidoh View Post
Leviathan was originally planned to be a Primal battle in version 1.0, but was dummied out along with Titan, because of the tragic Japanese earthquake and tsunami in 2011. Square Enix considered it to be in very poor taste to feature summons in the game which cause earthquakes and tsunamis so soon after the disaster, and hence their battles were never available in the game, although their models were in the client's code.

That's no longer considered an issue though, so expect Leviathan in ARR eventually along with Ramuh (a teaser of Ramuh's battle music was released a while ago by SE as a sneak peak about what to expect).
i remember seeing a post somewhere of a screenshot of what looked like a big crystal in the water off a pier, one of the players postsed saying it might be for a unreleased primal battle against leviathan