being noelle's personal servant and bodyguard worked well for you. you got to know the girl so well that she opens up to you. but, now that you're both here in the black bulls and she's stronger now, what's the point in you staying? you only became a magic knight for her. obviously, you're both pretty attached to each other as it is. however, you never thought about what you wanted. and now that you know, you can leave. you can pursue a different life.