Yu dayun's entire existence was a massive coc*block imo. This would've been a fantastic manwha if the MMC was the sole MC.
"Stop fighting"
That one scene made this manwha a 110% less interesting.
Things could've gone way worse, sure. yu dayun could've acted like his brother was a monster and make him feel guilty for fighting in self defense.. thank god that didn't happen. But regardless, If there's anything that kills my mood in action animanga it's that one weak character that always gets in the way screaming "Don't fight, the bad guy might get hurt !" and here yu dayun plays that role.
I guess I'll just read weak hero. Grey in weak hero doesn't have anyone holding him back, thankfully