Comment by SmallPP but i made her proud on Childhood Friend of the Zenith - Chapter 103

Quite a few things are going to happen. Gu Yangcheon will be punished for the murder of the elder and the subsequent prison break. His father praises him… a little? Moyong Hi-ah will play a role. She makes a contract with the Gu family that is very profitable. In return, she is slowly healed by Gu Yangcheon’s flames. And I mean really slowly—it takes years. That means Moyong Hi-ah will be around with us for quite a while.

His punishment is solitary confinement, which means he has absolutely no contact with anyone and just sits alone in a room. It’s basically an offscreen training arc for the MC. There’s a time skip—I don’t remember how long exactly. But once he gets out, he’ll be significantly stronger. And now, brace yourself: our beloved Wi Seol-Ah has already left the Gu family by that point! It takes quite a long time before she appears again. We might get brief glimpses of her, but nothing more.

After that, I think he goes to the frontlines together with his older sister. Of course, his fiancées follow him, along with the poison girl and the ice girl.

But I’m not completely sure about everything. Some details might be a bit different, or I may have forgotten important information. This is just a rough summary.