User blog comment:Yellow Ledbetter/New Assassin?/@comment-4697965-20120302011436/@comment-4809082-20120302020509

If you look his left arm closely you will see his hidden blade in this image http://images.eurogamer.net/2012/articles//a/1/4/6/3/2/5/7/AC3_X360_2D_NORATING_03.jpg.jpg

And it seems they are double hidden blades.