The whole reason why she isn't making a contribution when fighting monsters is because of her anonymosity. The world thinks that she's dead, if y'all forgot (which I also did ngl lmao). She's in hiding rn. So helping Ji-han would be counterproductive to the plan as it will shoot her up the rankings and make her name visible to the board and, hence, not anonymous. Now, she'll probably defeat this boss monster and her ranking will change and her name will be shown in the board. So don't be impatient, there'll probably be more action from her now since she isn't gonna hide anymore. There isn't a reason to hide now that she's determined to kill the boss monster and accept the consequences.
Brunheart is absolutely adorable, a little princess fits her image so perfectly!