We've seen Nic call in his favor from Mab in Skin Game. If I'm Nic I would love to get Ivy just to have leverage over even more people. Also, ever wonder what he did for her, seeing how we've read what Mab's repayment allowed him to achieve? Maybe she's Queen of Winter because of him? Or a severe threat to her throne was thwarted thanks to him? 1000 years ago was a completely different white council. What might they have been like? Possibly writing the last of the laws? maybe there were only a few, and the disasters they saw caused new limitations to be decreed?