ALPHA QUADRANT
Revenge was an unknown concept to the Borg because they had never encountered anyone capable of defeating them, until now.
So as the Borg Cube finally lost its battle with the artificial black hole, created by yet another unknown, a substance simply termed Red Matter, the collective hive within met their end in the knowledge that the probe they had launched had cleared the rupture in space, and was now hurtling its way to the far reaches of the Delta Quadrant. The information it carried they believed would lead to a suitable reprisal.
But they had miscalculated.
DELTA QUADRANT
Upon its immediate arrival at the Unicomplex, the data relating to their demise was deemed immaterial to the one who accessed it. She had evolved to be the only member of the collective capable of disengaging from the hive mind, to reinstate the capability to maintain individual thought, an ability for which the Borg Queen was truly grateful.
For her interest had been piqued by the other data that had been collected, specifically pertaining to the Federation Starship that had engaged the Borg Cube. In particular her focus remained on one member of its crew.
The one they called Khan.