Always liked Kaya, especially her basic version. She got nerfed some in Mk 2 (no more spirit door assassination runs) but every new beast gives her new tools to work with. That new-ish griffon is fascinating - long leash and innate stealth opens up a lot of possibilities, and it's gives Circle three(!) initial attacks off of a 4 point light warbeast. At effective MAT 8 with pKaya, there's got to be some potential there.