Zaer, while yes a knowledge planes check would be needed, there is also some things which are common knowledge, like the existence of a succubus. My point is that if her abilities are thrown around in front of us in a blatant manner, the DM (Depending on his style of play, I am not familiar enough with him to know what he would do) Could start handing out bonuses to any checks made to discern her true nature, and having people with the ability to make those checks start making them when a suspicious activity arises. I'm not trying to be a dick here mate, but after the big deal was made about disguising your succubus, you have her running around in a thong bikini talking about kissing a necromancer to distract and weaken him. I mean, that is just about as in our face as you can make it without having her pop her wings out lol.<br/><br/>