As someone who got into stupid teenage angst fights with their parents, being threatened with homelessness is the fastest way for a kid to immediately assess fight-or-flight. Some people choose flight and back down, with all trust and bonds of family broken thereafter.
And some, like the ML, choose fight. Grandpa has only himself to blame for this outcome.
The author took every possible shounen hentai trope and threw it into the story. We went from monsters, to evil big government, to incest, to evil scientists, to tentacles, to now mpreg. And then the author slapped on the most stereotypical BL manhwa seme, complete with anger management issues and gym rat bod.
Why does this story annoy me so much.
IKR ARRRRGH MC MAKES MY BLOOD BOIL ヽ(`Д´)ノ