I pretty sure that Young Master Xehanort is voiced by Ben Diskin. He's the voice of Numbuh 1 and 2 on KND, Sai on Naruto Shippuden and Szayelaporro Granz on Bleach. In fact YMX sounds just like Szayelaporro Granz. ( you can listen here Skip to 0:35) Mayuri Kurotsuchi vs Szayel Apporo Granz...