The reason I included the part about recharging was because people (noobs) might use it too frequently. If it's a one hit kill, people will need to have some delay, otherwise they will just slash randomly. To be honest, I think Phlack's idea is the best method. If it could be done, I would think an entire spy pack would be good (i.e., disguise, cloaking, butterfly knife). It will be interesting to see if Racer includes a butterfly knife, and if so, if it can only one hit kill from behind.