The term Egg (卵, Tamago?) is used in the World of Magecraft to describe containers:
- Planet Egg (星の卵, Hoshi no Tamago?): One of the fundamental components of any Living Planet. It refers to celestial bodies that haven't been infused with an Archetype of Creation.
- World Egg (世界卵, Sekai Tamago?): Also known as Principles. It is the fundational theory of Reality Marbles and the origin of some, if not all, Textures.
- Celestial Egg (天体の卵, Tentai no Tamago?): Luminary Arcueid's Principle and a Conceptual Universe.