Olja

“The heroes cleansed our world of chthonic terrors -- earthborn monsters that endangered mankind and threatened to choke the rise of civilisation. So long as dragons, giants, centaurs and mutant beasts infested the air, earth and seas we could never spread out with confidence and transform the wild world into a place of safety for humanity.
In time, even the benevolent minor deities would find themselves elbowed out by the burgeoning and newly confident human race. The nymphs, dryads, fauns, satyrs and sprites of the mountains, streams, meadows and oceans could not compete with our need and greed for land to quarry, farm and build upon. The rise of a spirit of rational enquiry and scientific understanding pushed the immortals further from us. The world was being reshaped as a home fit for mortal beings only. Today, of course, some of the rarer and more vulnerable mortal creatures that have shared the world with us are undergoing the same threats to their natural territories that cuased the end of the nymphs and woodland spirits. Habitat loss and species extinction have all happened before.
The days of the gods themselves were numbered too. Prometheus's gift of fire, as Zeus had feared, would one day allow us to do even without the Olympians.”
― Stephen Fry, Heroes: Mortals and Monsters, Quests and Adventures