User blog comment:Subject 16*/Assassin's Creed: Revelations - News/@comment-78.147.240.75-20110516191246/@comment-168.221.158.44-20110518191622

The Sixth meaning Eagle Vision. Or that's my theory. Juno said that humans only have 5 senses but Altair, Ezio, Desmond all have Eagle Vision, enforcing the idea that they are direct descendants of The Ones Who Came Before.