Because he was a live-in son-in-law of lowly status, even his children had to take their mother's surname.
Then his wife's family fell on hard times, and his mother-in-law kicked him out, branding him a bringer of bad luck.
To escape disaster, he had no choice but to enlist, leaving his wife and daughter unseen for three years.
Fortunately, his military service turned him into the God of War from Hell. He returns to the city in triumph and makes everyone who looked down on him eat their words! He takes revenge on those who wronged him!
Who says a live-in son-in-law has to be treated worse than a dog? I am the Dragon Son-in-Law, a God of War returned from Hell! Got a problem with that? Bring it on!