According to the city inhabitants, the portal picks up on feelings of "displacement." I don't know about other species and can't speak to their experiences, but it's possible that's what's drawing in such a high number. Humans and restlessness is a pretty common trait.
I've also heard some say the portal may be sentient and therefore favor a certain population, but I don't have any proof of that.
text | un: detdecker
I've also heard some say the portal may be sentient and therefore favor a certain population, but I don't have any proof of that.