WEFOUNDLouie the Rune Soldier, Vol. 1

The king probably doesn't know Louie is his son, judging by his reaction in the ending. If he shares Louie's recklessness, the high priestess might've purposely hidden it from him; if he knew, he might "do the right thing," acknowledge Louie as his son, and send the kingdom into turmoil.

As noted above, High Priestess Jenny expresses an almost unmistakably maternal concern for Louie and seems very interested in his romantic life. She also has a cutesy pet name for him.

During the Mylee Festival, Louie notices a painting of her alongside Headmaster Carwes and remarks that she never told him that the two of them fought together in the war. She responds by smiling secretly and saying that she and headmaster Carwes are "quite close." It seems strange that both she and Headmaster Carwes would have neglected to tell Louie such an interesting piece of information, especially since Louie is both interested in and knowledgeable about the battle. They seem to be actively hiding the extent of their relationship; there must be a reason.