The Ex, former boss and junior get exposed and ruined. The grandpa ruins them so much that the Ex can't even work as a prostitute. They then try to stalk and blackmail MC, but this just triggers Grandpa and he decides to get rid of them, for real. Now this is where it get insane...
He banishes the boss from Earth... Yeah you read that right lol
He has her shipped to space thanks to his connections, then taunts her over a msg saying "you threw him out of a place he loved without listening to his side, now i'll do the same thing to you". She keeps crying and cursing her self for what she did until she died.
The junior got it even worse. He is imprisoned for 30 days, the guards are paid by the Grandpa to torture him all the time. They crusife him on the roof for the sun to burn him all the time. He thinks he can hold on, it's just 30 days... But then after the days pass, he thinks that's it, but then wakes up in the hospital to find out all that torture was actually in his head and only 1 min has passed, not 30 days. Grandpa had him take a special untested drug, and will continue to do it over the real 30 days. Do the math, it's actually 1000+ years of pure torture lol
After that he's mind is gone and is released. Walking like a zombie down the road a truck hits and kills him.
As for the Ex, this one is kinda lame, a detective just takes her away somewhere as far as i can remember. She is either killed of or imprisoned for life.
I maybe wrong on this one, but don't thinks so. Anyway, she is out of the picture...
As for the MC and his life
He has 5 girls. The twins, his step sister, the Novelist he supported (Grandpa's girl), and grandpa's bodyguard. Grandpa loves the MC like his own family, so that's why he did everything he did. He even made Japan accept harems by law, because MC didn't want to chose 1 of the girls and hurt the other 4.
So he marries all of them, the bodyguard (best girl by far imo) and the novelist end up pregnant at the end of the story. Everyone is happy, the end.