I came upon his story and after reading in all in one day this really fell off hard. The story took a complete turn for the worst with barely any consistency. Not only did it switch from the main premise of the story but the MC does a 180 and becomes the biggest piece of trash he hated the most. I don’t know if the author is doing this to set up for a redemption but it won’t be able to be done properly without feeling like trash and the other characters from his previous school just feel like small scapegoats to fuel how much the MC changed. They have no value at all and could be done so much better especially the girl who’s in love with him.
"the MC does a 180 and becomes the biggest piece of trash he hates the most."
That's the entire point. The MC even choosing to fight goes against what he believes. The MC never liked fighting, but he was forced by Maria to choose a life of fighting as a way to find his sister. You can see him adopting a sense of ruthlessness throughout Maria's conditioning because he has to get into Fight Class 3 and that class, from what we've heard, is very ruthless. It's a cycle of violence. Jitae's father killed Maria's family, in turn Maria trains Jitae to inflict pain and kill others. Jitae has only adopted this ruthlessness because that's what he has been shown at every defeat. From his father kidnapping his sister and beating Jitae, to Maria grabbing Jitae and yelling at him, to Young-Woon almost killing Jitae. Jitae is adapting.