The best candidate is the very primal that ravaged Eorzea in the Calamity: Bahamut. The extent of his wrath had exposed nearly all Eorzeans, the Warrior of Light included. By meditating at the site of Dalamud's break-up in the Carteneau Flats, the Dreadwyrm Trance should be achievable. ...
There is also another crustacean involved with the docks, a giant enemy crab known to the pirates as the “Calamity Crab.” This creature will wander around the entire dungeon in search of players, savagely attacking anyone they find. Both running away and standing your ground are valid option...