Also abundant in the Marvel Universe are legendary creatures such as gods, demons and vampires. The 'gods' of most polytheistic pantheons are powerful, immortal human-like races residing in other dimensions who visited Earth in ancient times, and became the basis of many legends. However, all of these 'gods' share a common ancestry and connection to Earth due to Gaea, the primeval Elder Goddess that infused her life essence into all living things on Earth. Gaea is known by various names and appearances in other cultures and among the various pantheons, but she is the same being. As a result, she is a member of every polytheistic pantheon of 'gods' worshiped by humans. Besides mythological gods, many deities made up by Marvel writers exist as well, such as the Dark Gods, enemies of the Asgardians. The Dark Gods are a race of 'gods' that have been worshiped by extraterrestrial races. Well-known alien races like the Shi'ar and Skrulls also have beings they worship as 'gods', though little has been revealed about them.