@Aichan Nothing happened with the sister. To summarize she said no and he accepted it.
#1 is probably the best guy in the series. He legitimately cares about his women.
To beak it down a bit
#1 comes off as kind of a douche at first, but he does his job and helps his friends when they need help. He isn't completely oblivious to the situation, but he also the only one who is actively trying to make children and succeeding.
#2 (main character) horribly naive and pretty stupid. Ignores the obvious so that he can keep his ideals in place. It's okay to be optimistic about things, but he goes beyond optimism to denial of reality.
#3 is a puppet. Basically being played by his "agent". He knows that he's being used, but doesn't really care anymore. Of course since the author appears to be a fan of M. Night Shamalamadingdong, there will probably be a stupid plot twist where "aha! you thought he was playing apathetic, but he really isn't. He just was just rolling with the punches until he could turn everything back on it's head"
#4 Who knows what the fuck is going on with him. Abused to the point of going insane? Probably the most logical explanation for his "transformation". his whole subplot with the cult changes mostly a sci-fi story into a fantasy story for no good reason. There has to be some ass pulls to get this story integrated into the rest. When the story reverts back to the isle of sadistic sluts I guess we'll get more details on that clusterfuck.
Then there's the other problem of linked relationships.
For #2 we know about his younger sister, but what is the status of his brother still in cryostasis? They took him to America when the Japanese UW was raided, but there's still a lot we don't know about that situation.
For #3 we have his sick sister whom hasn't shown up at all. Of course in true M.N.Shammy-lammy fashion they could have a twist where Karen is actually his sister Mayu grown up and hid her identity to help her brother.
For #4 we have his wife and his child. We don't even know if his child was a male or female when he was put to sleep so it's possible that there's a 4 year old male child being hidden somewhere in this series.