So guys as you know their's normally 12 Constellation but they're also the Ophiuchus who's less exploited. But why I'm talking about it? Well because it was going to be a secret Boss in OHOTSS before that i changed my mind so instead I'll give you some information about the lore:

Ophiuchus still exists in the world of OHOTSS she was one of the Constellation gardians but for some unknown reason she has been banned from the Constellation realm but she isn't trying to get her revanche so that's why you'll not see her in OHOTSS 1 but she will appear later

Also Ophiuchus looks like a girl but with some snake attributes (tail,tongue)