Due to its civilization of Water and Darkness, Aku is considered to be the "Evil" God while Zen is the "Good" God with the Light and Nature civilizations. After linking together they are referred to either the "Ultimate Transcendence" (or "Akuzen") and aim to stop the conflict between the Good and Evil forces.
While linked, they are the only God creature to consist of 4 civilizations.
Two "Saga" creatures were later released both with effects based around Aku and Zen.
After the resurrection of Ballom in his new Ballom Emperor, Lord of Demons form, the returned gods banded together to fight off the forces of the Darkness Civilization army. These gods included Aku and Zen.
List of Aku and Zen cards
- Aku, Ultimate God
- God Bringer
- God Saga
- Saga, the Almighty Creator
- Zen, Transcendent God
- Violence Heaven