The reason Guy died in the first game
Wain's grandmother was Lufia.
Arek the Absolute is THE MIGHTY GILGAMESH!!!Not only is the Lufia series now owned by Square(even though Square continued having Neverland develop the games) and since Curse of the Sinistrals has Arek speak about only wishing to adventure with Dual Blade and serving it's mysterious desires, considering Gilgamesh's obsession with weapons it's obvious that they are one and the same!
Alternatively, Dekar is GilgameshMemetic Badasses who are obsessed with swords and known to come out of rifts between parallel dimensions? Why not?