Not quite obscurity. She'd been active in Tir Tairngir for a while. As for the 'new Dunkelzahn', that was a clear angle she took, and it helped that none of the other great dragons were remotely interested in being the 'bridge' between dragons and the young races. Oh sure, Hestaby has her plots and plans, but then so did Big D (just look at that will). So no, not 'goodness of her heart', but she took things to a much higher level during the dragon civil war than she needed to if she didn't believe what she was doing was the right thing.