He's never cared for anything other than Abel. He was twisted from all the abuse and Abel is doing his best to steer the ML to the benevolent route (teaching him to be good when he was a kid, and he tries to do so again but Abel still sometimes treats him like a kid when he isn't anymore as we've seen with that last conversation)
The thing is, the dragon doesn't care for anything other than Abel's attention and seeing him smile, and even if Abel wants ML to be good, he also has too soft of a spot on him. In a way, I think there's a bit of twistedness from Abel as well.

I'm quite confused with the ml, it's like he just doesn't give a care anymore. Like a abel or no abel, if I'm bored I'm gonna burn it all. Everyone around him are acting for their own motives, I wonder if he is also