Assassin's Creed Brotherhood - the ending

[PZ]

Spoiler

I just finished the main story line, and the lines at the end are interesting:  Desmond has just knifed Lucy and the FC woman (not Minerva, but someone different) says "Only she needs to be found... find the 6th"

[mandru]

That was a puzzling comment.  I watched a video clip on that scene several times and still don't know what to make of it.   ????