Summoning Reaping Knives on someone change his weapon set to the knives, but there is a way to alter that :
After the Reaping Knives are summoned, the "target" cant change his weapons but can change his form : Spiritshifting or drinking a Potion of the Fearless Brute is allowed. When the form effect expire, the target return to his weapon set , and have as beneficial effect "reaping knives". The effect is now different : 5 focus per hit. Multi-hits weapons generate quickly the focus for the