
Jiwoo defeated so many opponents with his "maximum speed" skill , it feels like that made him depend on it too much.
Like ur master told u about the ability, still instead of gauging the situation first, u just decided to attack head on. U dont have the advantage to do that.
Ur master can do that cz he strong enough to back up any whimsical steps.
Like WHAT EVEN IS JIWOO'S POWER other than being fast?
he won mainly bc of MC plot armor and bc opponents didn't know or took down their guards like an idiot but it wont be always like that.
He got so many force control from people around him but it never felt like he "grew", had new skills or something
Everytime its the same old shit.
Why it's a technique that can be performed once in a lifetime?
Since they didn't say, you can asume whatever reason. In reality, it was just used as convinient plot armor for the MC, so he doesnt get caught now, and to ensure noone can match him in the future. its a very common trope. Other than that, my guess would be because the ingredients for it are only available once in a century. Or it might be because the energy you have to collect in order to perform it, is too much for you to gather it again? Idk.