The Fomor (Fomorians) are primordial gods from Irish mythology who play a similiar role to the Greek titans, being envisioned as malevolent ogre-like beings with great supernatural power that they used against the newer gods that would enventually become the ruling pantheon of Ireland.

The Fomor were thus driven into the sea and were blamed for many ills in the world, especially elemental damage such as flooding, storms and disease - outwith Irish mythology, the Fomor have also appeared as antagonist in media dealing with fantasy and/or theology.

The Fomor were seen as the gods of chaos and wild nature, which added to their already formidable image in folklore.