@Meow_
It's a matter of both standing and allegiance, basically ars and him are allied and likely to be so for a very long time, in situations like that sometimes transfer of personell was common, while a little rude, ars is still technically working for house canale currently, so it's more like working at a company and the financial division asks for a transfer of personnel from the base level employee position, but the low level employee's really liking their boss so they refuse the promotion, he's essentially a knight under a lord, while it might come off as rude, it's not entirely unheard of, especially if they were mercenaries, true loyal knights weren't as common as most historical legends like to portray, charlotte and ritsu however aren't mercenaries, they consider themselves loyal to ars specifically as such their lives and loyalty belong to ars.