Avalondra
Initially, I was like why is MZY so upset with Lu Jin. You killed his mother, used people he cared for to manipulate him for years, and expect him to be loyal to you? Then I remember MZY's mother and father, despite the abuse he received from them, he was still bent on getting vengeance for them because how they treated him was a norm in their family. So, I am guessing MZY's understanding of human relationship is truly messed up. For that reason, I doubt he would be able to feel any remorse or understand why he should feel remorse.