"Victory or Death!" affected everyone on the map. It was used by guild NPCs in GvG matches when a match lasts longer than 18 minutes. Guild Battle NPCs march out of the Guild Hall in three waves; the first wave arrives at the flag stand at 18:45, the second wave arrives at the flag stand at 19:00, and third wave (Bodyguards and Knights) arrive at the flag stand at 19:15. If the battle lasts 20 minutes the Guild Lords will also move towards the center and use this skill. This skill is designed to end the battle quickly while not biasing the match toward either team.
This could be a reference to a letter written by William Travis during the siege of the Alamo.
A likely shout-out to this ability occurs during the second-to-last EotN cutscene, titled "The Great Destroyer." At the end of the scene, a certain character shouts "Victory or death!" as a battle cry. This is especially poignant considering that EotN may mark the closure of the first Guild Wars' storyline. In that sense, this penultimate cutscene is the "victory or death" moment of the larger "guild battle" (storyline) of the game. A bit of a tearjerker, really, for long-time fans who read between the lines.