Spoilers if u havent read the 8th book dont read. When  Tui decided to not make a book about her it blew my mind because the skywing died and Clays' sibling ran off. then she got injured, This is my idea on it, maybe Tui thought that Kinkajou would be no offense useless to make a book in her point of view because Darkstalker is back and what use would it be to be in her mind? because she is no use against him. also it broke her tradition of writing all the povs of their friends.