I agree that show is a mix of nice ideas and atmospheres, and other parts are dull and not worth watching.Regarding the god arc, since it comes from the same type of cells as the Vajra and all of the monster group, it's not surprising it has régénération abilities.
If I understood the snipets, this is a group of cells with a main one reigning.
We can suppose that if the main cell isn't destroyed, it can be revived with the proper nutrients and energy. So the capsule and the interaction with bloodstream probably indicated that.