oh, Persona. in PJO, the Roman and Greek monsters, gods, and spirits are around, alive and well. i'm sure Nico's met Orpheus, too, since he's in the Underworld a lot. son of Hades right here. so as far as sensing things, he'll only be able to pick up Orpheus, Thanatos, and probably the Fates, since they generally stay in the Underworld. depending on how Ares works in Persona, maybe him too? in Percy Jackson, Ares gives off this anger aura that just makes you wanna punch things whenever he's around. if that's a thing in Persona too, he'll be like "Hm." Otherwise, nah.

the things from other folklore won't hit any of Nico's pings.

i am so amused though, holy shit. Nico may geek out if he finds out Makoto has all these dudes, just a fair warning.