Christianity, and it did.
well in Greek mythology Medusa could turn people to stone by looking at them.
you can't beat Greek mythology, because they think the gods are real, today the god of Greek mythology are not to think of much. the Greeks thought the gods are the most powerful,immortal, gods of Greek. and if they were real(not saying that they aren't) they could kill, if interfered. plus, you don't know where they are because they can turn into human form. so the answer could be no, you can't beat Greek mythology.
a pure white horse that could fly
This was Poseidon.
No one could kill Eros. In Greek mythology the Greek god Eros is immortal.
Hades had an invisibility cap, or helmet.
Orpheus, out of Greek mythology.
The Siren(s)
the closest you could get is in Greek Mythology, Athena, goddess of wisdom.
In Greek mythology, Zeus was known to have relationships with both men and women, so he could be considered bisexual rather than gay.
I think you mean Nereus, but I could be wrong....