[@Kimono] I tried looking up the sheet for Gian but I think [@Savato] never posted it. Not publicly, as I have it in my PM's, but you'll have to ask him. 

Yes, the next arc is after the 2.5 year timeskip. It'll be Masaki's arc and I think it'll revolve mainly around demons, but don't quote me on that. Typical age range.. I think so far we've seen characters 16 and up, with most being around 16, and a few above 20.