How does this assasain build sound?

[Bob the Beholder]

Please forgive me if I'm wrong, but I remember, from back when the expansion was new and I was going all crazy over it, but doesn't the Shadow Master only use skills that you have at least one point in? In that case, it won't use Death Sentry unless you put points in it anyway, and I imagine there are quite a few prerequisites you'd have to get around.