
Shin should just stop trying to get Wolfgang married. There have been many kings that haven't been able to have kids and their successor was some relative or someone else. The Swedish queen Kristina didn't have any kids and her cousin became the king after she abandon the throne. Karl XII didn't have any kids either and after he was killed his sister became Queen, who also didn't have kids. We have had several kings that weren't even related to any kings at all.
So Shin should just chill, live happily ever after with his Wolfgang and adopt some random kid and make him or her king/queen.
I'm worried that if Jin doesn't get to experience something positive soon, everything will be too much for him to handle and he will try to take his life in the end.