Lupin marries Fujiko, everybody gets what they want, and nobody dies. The end.
I like this one
Except it can't happen.
How can Lupin live happily with Fujiko in marriage if Zenigata is still around?
Zenigata want Lupin arrested! Lupin can never settle down like that!
Sometime I think Monkey Punch specifically made the characters so it is impossible for them all to be happy at once.
Mr. Foo, it is entirely possible for two people to be married and not be obligated to live in a suburban home with a bunch of kids the rest of their lives. If Lupin and Fujiko got married, they could continue to do what they've always done, they would just now be a couple. And they've had sex multiple times, so I don't think the possibility of having unexpected children would be an issue either.