Well the tadpoles are already tied to the Absolute. They allow the Absolute to invade the mind of the host and give them power, and those with tadpoles are acting as sub-lieutenants commanding forces under the Cult of the Absolute.
But I’m sure the true motivation for this, and the identity of the Absolute (probably Bhaal, if not the combined Dead Three) will become evident at the end of act 1, because that’s how narratives usually progress.
