Context: Someone(アスタリスク) is about to have his ceremony to become a knight.
My question is about the first part where it says 平和と安寧を司る者. As I understand it, this sentence is implying that he is a 平和と安寧を司る者. From what I've seen the usage of 司る is used to represent someone in charge of something, but アスタリスク isn't a knight yet, or anyone special who has been tasked with ensuring peace(at least before he takes this oath) or anything like that, he just does it because he wants to do it. The usage of 使命を全うする to me also implies that it is something he has been tasked with. My question is whether these things can be used to talk about things that people have taken upon themselves, or am I misunderstanding something here?