the blue one in my book was always the sea serpent limsa ended up fighting.
(and succesfully defeating)
seeing as the current primals show forms of high intelligence and the ability to speak;
(something the blue leviathan never displayed if i remember correctly)
i'm assuming the purple/pink one will share these abilities and be the actual primal leviathan.

also:


SE for the love of god. make his battleground a ship. during a bad storm.