Quote Originally Posted by Anonymoose View Post
It's possible that it was another entity, but everything says Leviathan to me... it's in LL, its presence correlates with treasure taken from an island said to be the mythological place Leviathan is bound to, it's heavily ingrained in Limsa's lore, and so far the only sea beast we know for sure is is Leviathan, and we see it destroy several boats with what I must assume was Tidal Wave.

Much like my standards for discounting an assumption until shown otherwise, that's just too much for me to not make the assumption until shown otherwise.
The bones pretty much show you that it's just other entity the story could be something else. Remember what npc tell us could be lies also it could not be the 100% true because it a story told and told again over and over and things change in the story just like how many history stuff we learn we not 100% sure.

So i say that it's not leviathan it just a random big fish in the sea lol maybe a power beast but just not a primal. hoping the dev would tell us something about it so we really know