I've been kind'a interested in Blue Archive, but just been wondering:

I've heard a lot that Sensei is a completely depraved degenerate. I saw a CG of him having put a blue-haired girl in a collar, and from what I've heard that's apparently presented as a "Stress relief" event for her. Okay, sounds good. But then I heard that Sensei also gets put in a collar and gets made into a Sub for a bunch of the girls.

How true is that? I'm not really interested in any kind of femdom stuff. And, while I think it's weird for a teacher to put his student in a collar, I can at least go along with that to some degree. If he's gonna be like Issei in DxD where he's just super eager for any scraps of female attention, and will debase himself into all kinds of fetish stuff, that's less appealing.

Secondly, and I guess slightly less importantly. Does it do the "Choose your gender" and then change the pronouns to He/She like GFL? Or does it do the Nikke thing of always saying "They"? Not a huge dealbreaker, but I've always found a lot of the "They" gender neurtral stuff reads extremely clunkily.

Thirdly, does Sensei speak? Or does he only talk in dialogue prompts?

I have attached an image of Nagisa, whose picture I saw and made me think "Wow, she's really cute."