The Heavenly Paradigm was Time Lord technology, capable of changing the timelines so that the best possible outcomes were always acheived in every decision made. The device required a substantial amount of temporal energy to be activated, after which its own edits to the timeline would produce energy of its own, making the process self replicating.
The enormous energy requirements were the only thing stopping the timelords from activating it. If they could have got it working it was to be targeted at Skaro and rewrite the Dalek's timeline so that they would attain the best possible future for themselves. With no need of war or dominance they would have prospered alongside the Thals and never engaged the timelords in the Time War.
The War Master used the Heavenly Paradigm via the death of Cole Jarnish to alter the timeline of the entire universe. While the Paradigm at first appeared to be working as intended, ressurecting entire races and worlds throughout the universe, it was unable to effectively calculate changes that would benefit the universe at large. Proving a double edged sword the changes continued, writing planets out of existence and even undoing timelord victories which led to the outcome of the battle of the Cruciform being a Dalek victory, allowing the Dalek Emperor to take control of the Cruciform and the change of the history of numerous planets. The Heavenly Paradigm at last overloaded, the resulting explosion destroying the timelord base it was housed in. (AUDIO: The Heavenly Paradigm)