In the case of Kaula kundalini yoga, the ultimate divine was in fact Shiva.
Just as ātman attained union with brahman, so too the Kaula adept sought eternal union with Shiva. This also meant moksha, or freedom from rebirth.
The tradition of seeking Shiva as the ultimate god has particularly survived in the Himalayan regions. Of course, this is also the area where Shiva is traditionally said to live.