Koumyou's arm . . . hm. I seem to recall that the images of dead Koumyou show him as having lost an arm, but I'm not sure whether or not they specifically say the youkai took him away.

However, when Gyokumen's giving orders to barcoded-Kougaiji, I have a vague memory that she told him to bring back Sanzou's sutra "and one of his arms". Are we cross-correlating to that here?