So the most intriguing detail to me revealed at Fanfest tonight are these entities. These must be the "trancedental beings" that Kuribu and the Amdapori Lion are based on. Which leads me to think the "Holy Cow" of Eureka Pagos might be a Sin Eater too that showed up in that crazy hellscape.
Of course, what I'm really wondering now is: was Ultima, the High Seraph a Sin Eater that Ajora summoned...or something else? I wonder if other Sin Eaters have appeared already.