Here's a message from HELLHOUND, as posted on their myspace page :

"Swordmaster, the bassist/one of the HELLHOUND founders left the band after the show at Sakae Tightrope, Nagoya on May 3rd, 2010. We deeply appreciate all of his efforts and major contribution to us HELLHOUND for these years, and really wish him a future success. We still haven't reached any decisions as for the replacement and our future plans yet, but will soon get prepared for the production of the forthcoming new album anyway. We'll keep you updated.
HELLHOUND
June 1st, 2010"