There were were many gods, all of whom were immortal (live forever), the greeks believed the gods lived above mount olympus and watched over them. There were three brothers
Poseidon, Hades and Zeus. All brothers wanted power so poseidon got the sea. Hades got the under world. And Zeus got the heavens witch meant he ruled the other gods.
Hercules the son of Zeus was extremely strong and performed 12 nearly impossible tasks. Perseus the son of Perseidion, killed Medusa a vein mortal that was turned into a monster.Achilles his mother dipped him in the river stye and became immortal but had a weak point Achilles heel.
Many stories were made after these gods and have still not been forgotten.