Ianor's story (although heard secondhand from the demon) shed more light on the situation if he could be believed. Maldine had been the illegitimate child of a minister and was scolded for speaking out of turn during a meeting between elf and fairy leadership.
Azariel had liked his idea and purposely chose him to be the next ambassador once she became queen. That would explain his personal loyalty to her but not why he went so far as to accept demon magic.
Kael had no idea the blood bond wasn't solely a fairy thing but it made sense. Demons were the primary magic users in their world.
Finding out that Zeldris's ancestor formed his faction was startling as well. He hadn't been aware they had been around that long but it made sense in hindsight. A lot of things did so he was inclined to believe the fairy's story but that didn't mean he trusted him.