You broke up with Diavolo cuz you'r human, and he's a Demons King he didn't agree to that, and tried to kidnap you, but he was caught by his father and imprisoned, you were sent to your world he was deeply depressed by your absence. Weeks passed and he did not rest cuz of nightmares. One stormy night, he saw you in his dream with him, then it's changed when you stabbed him, he woke up frightened Diavolo: dear ,plz no. I love you to death. he spared his wings ,broke the chains. he's coming for u