: Flavour text implies the Watcher defeated Mazzarin, and
: its not clear whether shadification is a voluntary or a
: forced procedure, or both. Hence it is not illogical that
: a defeated Mazzarin becomes a shade under the control of
: the
: Watcher.
A flavor text speaks of Turquine agreeing to become a Shade, and GURPS characterizes shadification as an "exchange" made by the subject. And every reference to a Shade's previous life--both in GURPS speaking generally and in the game as Turquine--paints them as evil bastards who very much desired to become Shades. I think it's most likely that the archmage has to agree to his conversion. In any event I suspect Mazzarin would have suicided immediately if he thought he was in danger of being taken alive by the Watcher.
--SiliconDream