User blog comment:HELO/How I Learned to Stop Worrying and Love the Catalyst/@comment-24174486-20120710232656/@comment-24174486-20120711212443

"Okay then, what's 'Vendetta'?"


 * Spoilers ***

Vendetta is the Prothean VI you find on Thessia. It gives you information about the Crucible, including mention of a "catalyst" that the Crucible needs to activate. It also infers that the Reapers are "servants" to something that created the cycles, but that it doesn't know what the creator is or why the cycles were created. It's stolen by Kai Leng, and when you find it on Cronos Station, it tells you that the Catalyst is the Citadel.


 * End Spoilers ***

"the character who is ultimately the main villain for the entire series"

The Reapers were the villains for the entire series. The Catalyst was merely the creator. You were not trying to stop the Catalyst for the entire series; you were trying to stop the Reapers. And in the end, you stop the Reapers, not the Catalyst.