Its short for Kuroi Kenshi, which is the original Japanese equivalent of "Black Swordsman." I still like Berserk, but when I was 15 it was my favorite series so I used that name. Eventually just the Kenshi part stuck so I've used it everywhere, which is for the best since on my old handle from 2005-2006 I was constantly hacking forums by tricking people on Invisionfree into making me admin by any means necessary (impersonating their friends knowing they wouldn't bother to require email confirmation, being the most active and amicable member while plotting to ruin the forum because the admin rubbed me the wrong way etc.).