Yami pulls everything in. Symbolically, it’s the “return to origin.” It may be the first key, the anchor for the god’s essence to stabilize inside Teach’s body. The void where it lives.
Gura could be the fruit that cracks the seal holding the god dormant when the time is right.
Third fruit, mythical Zoan, likely embodies creation or rebirth. The full consciousness that makes the being rule again.
The final antagonist was Exodia all along.