Eternals were Transcendental beings beyond anything the human mind can comprehend, the only ones who know about their existence are Overgods and Voidlords and even among them the Eternals are a mystery. They never interfere with mortals unless it is to delete evidence of their existence, something the master tends to do.
Biology and AppearanceEdit
Eternals had no form, if they decided to appear somewhere on the Mortal plane they would normally take the form of some mortal but this has only been done once.
Eternals are true omnipotent being possessing power over time, space and existence itself.