The robe would probably have to have a substantial amount of AC, considering the fact that it covers the head. In this fashion, a helmet could be unwearable, but made up for by the robe's added AC / Stats.
The jaggedness of the blade needs to be worked on. The blade looks very lopsided, and almost like torn paper. Consider stuff on the following page for designs. (Googled results ftw. ;])
http://home.att.net/~steven.licata/swords2.html