Another rare entry on this list that is not from either the Dominion or Klingon Wars is still perhaps the most famous battle in Star Trek history: Starfleet’s engagement with Borg forces in the Wolf system, just eight light years from Earth. Compared to other conflicts mentioned here the numbers involved are much smaller in scope, 40 Starfleet vessels and a single Borg Cube. But Wolf 359 is devastating for the trauma it impacts on much of Star Trek itself in the years since its aftermath was first revealed in the iconic TNG two-parter “The Best of Both Worlds.”
Thirty-nine of the 40 Federation vessels at the battle were destroyed, including the Saratoga, the vessel where Commander Sisko served prior to his assignment to Deep Space Nine—and where his wife was killed during the battle. Wolf 359 was the engagement that saw Starfleet begin to develop the Defiant-Class cruiser, its first explicit warship designed in its history. And, of course, all the more devastating and most explored in the years since is the fact that all this carnage came at the hands of one of Starfleet’s most legendary heroes: Jean-Luc Picard, assimilated and transformed into Locutus of Borg, who would be haunted by his actions, even after his successful reclamation from the Borg, for decades after the fact.