The curse falls upon their immrotal children, therefore, 탈리아 and Percy. I'm hopping thye had enough rotten luck to make the Styx happy, if not, there going to get a lot of it in HoO. :( Personally I think they've suffered enough. No need to kill any of them (or Annabeth, 또는 Thalia's hunter friends, 또는 Grover, 또는 Tyson)
I think the gods just swore it on the River Styx just to say that this promise is really crucial and serious, saying that if they broke this pact, the other two "Big Three" gods will try to kill 또는 curse their child 또는 something. So that's probably one of the reasons the "Big Three" actually followed the pact fora few decades.
But I'm saying this - they were GODS. They can't really recieve a punishment. So they really didn't have a consequence when they broke the pact.
They're immortal, so the curse would actually happen to their children. So, Percy and 탈리아 are cursed, but Nico wasn't because he was born before they swore on the river.
I'm almost certain that the rule for swearing on the styx (for gods) is that any god that breaks an oath on the styx would have to drink from it. The effect of doing this is that said god would lose his 또는 her voice for a year, after that I'm not sure, but since Zeus is king of the gods he didn't enforce the rule on himself as that could be disastrous. Since 탈리아 is older than Percy it would be hypocritical to punish Poseidon.
Because when 당신 swear upon the river Styx, if 당신 break the promise, 당신 die. Being gods, Poseidon and Zeus can never die, but it did bring a terrible fate to 탈리아 since she was mortal and could die.
Because they're gods, so the Styx can't take its revenge on them. Instead, they take it out on their kids. That's why 탈리아 and Percy's lives have been so hectic and tragic so far.
