each of them give you "friendship" rings but when you walked to Olympus everyone said "Happy future marriage with Hades and Poseidon" that's why you turned the rings into two butterflies one is black and other is blue they're hidden in you're private garden who is guarded with 10000 eyes monster and after that you turned into mortal and hide 10000 has passed you're mother Nyx and Poseidon with Hades already forgot about you