Potency is the power trait that rates the general power of Gods as between themselves. An ogre and a young god might both have a d8 strength, but the Potency of the God is going to be a huge leg up in any battle between them.

Potency also comes with some free SFX:

sfx – Resistant – step up and double Potency die in any dice pool to resist mental or magical attacks.

sfx – Invulnerability – spend 1 PP to ignore physical stress except that caused by [TYPE]

[TYPE] equals Sovereign Metals plus possible additional materials as per Potency rating below.

sfx – Divine Resilience – Drain Potency by 1 step to recover all stress and a single step of Trauma. Recover only through your Source.

sfx – Empower – shut down your Potency Die to step up or double another power die, Recover on your next action where you do not use empower.