Deathstroke stated his demand: they had to take him to Mother Night. As fellow embodiments of the concept of "The Void," the two understood each other best. If Mother Night were willing to help, dealing with Pralaya would become much easier.
It was not impossible to go straight to Pralaya and throw down. Assuming the difficulty was around 100, finding Mother Night's help might reduce it to 3 or 5.
Once The Void countered The Void, Pralaya would be nothing more than a lump of flesh. Dealing with her would be absurdly easy.
The difference between humans and animals was that humans made and used tools—including human tools.
So his original plan had been to seek Mother Night's help, though there were a few difficulties to overcome.
First, Mother Night's location was extremely mysterious. Only the Endless knew where she was.
But Destiny was dead, it was impossible to tell whether what Delirium said was true or false, and Despair was a defeatist, so none of them could be relied upon.
That left only Desire, Destruction, Death, and Dream as potential guides.
Second, persuading Mother Night might prove difficult. Her stance had never been on humanity's side. As The Void, she too hoped for All Things Return to Nothingness. The difference was that, unlike Pralaya, who actively pushed for it, Mother Night chose to wait.
She waited for all things to perish naturally, for the universe to collapse naturally, for everything to reach its peak and then gradually return to nothingness after blazing like oil thrown into a fire.
Pralaya was radical, while Mother Night was relatively passive—the difference between Infinite Consciousness and Infinite Unconsciousness. Yet when it came to All Things Return to Nothingness, the two sisters actually shared the same stance. Persuading her would probably require some underhanded