Responses
I think they know that he is strong but they just don't know how strong bc we saw his past and what's his capable of but they just saw half even less plus him following her to the enemy base wasn't in thr plan and they didn't think of it so ofc they would be surprised
Whenever things happen like ya know for example when the guy in chapter 24 came.
That character whom proposed to yuna so that they can both be engaged and got angry cause he noticed that yuna had a thing to yu ijin and he thought they were both together, then suddenly he proposed that their body guards should have a sparring or something in chapter 25.
Yuna and her sister tends to act like (Oh no!) Whenever it comes to yu ijin not only them but some of the character's too, i can't really put it into words properly but. GIRL'S you have seen what our yu ijin is capable of do you really have to act like that UGH you should act CONFIDENT ┻┻︵ヽ(`Д´)ﾉ︵┻┻ (SIGH).
why am i even saying this they're just a written character's ( SIGH) ┐(‘～`;)┌
Well don't mind me guys im just Fan gUrlinG OvEr YU IJIN (人*´∀｀)｡*ﾟ+ My BaBy is Strong (◠‿・)—☆
I wish everyone who read this a great day no matter which country far or near i hope you are doing well may god bless you all (≧▽≦)