"Kami Tenchi" (神 天地, God of Heaven and Earth) is the supreme being of the official Tenchi Muyo! continuity.
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Origin: Tenchi Muyo!
Classification: Transcendent Deity, Supreme Being
Attack Potency: Absolute Infinity
Lifting Strength: Irrelevant
Striking Strength: Absolute Infinity
Durability: Absolute Infinity
Stamina: Absolute Infinity
Range: Absolute Infinity
Standard Equipment: None
Kami Tenchi is a transcendent entity that is as incomprehensible and boundless an existence to the Choushin (who are already transcendent in relation to dimensions, nonexistence, logic, and any scientific theories), as they are beyond the understanding of ordinary beings.
It is also harder to argue that the entity should be High 1-A, rather than tier 0, as he does not have any known relevant minor limitation, nor does he have any being above or equal to himself.
"Kami Tenchi" is technically a fan name. The supreme being has not been given a distinctive title.