Well, I was discussing it with someone else, but we think there might be more Reapers out there outside the ones we just met. Of course, it could have just been a random number they decided on, but one of the Reapers did say that it wasn't as if there were six of them.

[ of course, Setsu tends to just overanalyze every little thing, so it really could be nothing. it really could just be three..... ]