Nah, none of the vtubers are AI nor are they designed by AI, the company's Twitter account has most (all?) of them listed with a short clip and credit to the character illustrator.
Further looking through their site... it gets worse. It looks like they have a "We'll only support the ones that make us money and let the ones that don't rot away" mentality.
A unique virtual talent academia committed to expanding creator potential and elevating Vtubing as a respected profession. Join a community that fosters talent and redefines entertainment.
nexas.live
Forget black company, this is Vantablack company tier, just next level of black. The working environment amongst them is going to be ultra toxic and a backstab galore.