I like the idea of Dark Types being into bondage, I already played into her enjoying the lack of control when the MC was capturing her.
I might see if I can write a few bondage scenes, but you're right that there's not many Dark Types to work with, so it probably wouldn't be a regular occurrence like the AWC.
I'm not really into bondage either, so I'm not sure how good the scenes will be, but I can at least give them a go