[ Even gods? Maybe Raidou would be able to summon something like Ryoji himself, which puts him in the same class as Minato. And so many of Minato's Personas were based off the very ilk that Raidou mentions...

Nodding along: ]

That's not unlike the summoners I know, though instead of demons, they use Personas — put simply, the manifestation of cast-off human emotions that have been tamed. Many of them take similar forms to what you've mentioned. For instance, one of them took after the form of Orpheus, the figure of legend who played his harp and tried to lead his dear Eurydice out of the Underworld. There are Shadows that capture every emotion conceivable, and thus there are Personas that do the same.