People, all of them have tempers;
Zheng Fan has always been restraining his own temper because he is a reasonable person.
He understands Mo Wan's attitude towards him. Indeed, he created Mo Wan, but it's reasonable for Mo Wan to hate him.
Because when he designed the "Mo Wan" storyline back then, he didn't hold back at all. Even though they have a "father-son" relationship, which father would treat his son like this?
Therefore, Zheng Fan can understand Mo Wan, and he feels guilty about it.
As for these demon kings, Zheng Fan didn't repeatedly bring up what he had done for them, nor was he even comfortable mentioning it;
To put it bluntly, that was just him trying to savor the remaining years after finding out about his terminal illness.
Zheng Fan is grateful, grateful for the demon kings who "cared" for him during the six months he was unconscious in this world, and waited for him to wake up.
