14 sorta does have a central villain with Elidibus, but unless they wanted to pull from the Lahabrea, Nabriales, and Ascian Prime fights, he doesn't have to work with.
The producer of 14 also said that he'd want Nael van Darnus or Zenos yae Galvus as villain reps, and I could see either of them working well. Nael is a proxy for one of the single most important entities in the game (Bahamut) and gives us another spear user
and Zenos is mad popular and I could see his weeaboo samurai sharingan being fun.
(Also give Kain an estinien skin with unique voice lines, just for kicks)