The Lost Heterodoxy lexicon is a wide lexicon that is vaguely pentagonal in shape, with a flat tip and a small, semi-circular chunk taken out of the top and bottom of each cover. Its border is indigo, and its covers are dominated by an abstract, green symbol with a white outline and a white circle in the center.
A heterodoxy is a belief system that is different from the norm, but not heretical.
The Lost Heterodoxy has a simple combo that is very similar to many other of Zexion's weapons. The ground combo starts with a downward strike, followed by a slam to the left and right, ending with a forward toss. In the aerial combo, Zexion will do a downward, then upward strike, then throw the Lost Heterodoxy in front of him.