I don't remember my first book, but I think it was Trash of the Count's Family and Omniscient Reader's Viewpoint that mainly led me into BL because oh my g** the visualization of KDJ + YJH~ and although I really do see most of the relationships in TCF as familial, I remember really loving Cale and Choi Han and even thinking of a fanfic like, "the prince's sworn brother and the prince's instructor," written from the perspective of Alberu... my first duo was actually Cale and Alberu since I thought they had better chemistry but after considering that Alberu is a crown prince and soon to be king and Cale wants a peaceful life their desires and needs kind of clash and, "the prince's sworn brother and the prince's instructor," is really shippable, anyways, I digress. 