Cheng is an archaeologist and the first victim of Laocorn and his gang, having been attacked by them on an expedition. He survived the attack only to become corrupt and evil.

Some consistency with Cheng's base voice would be nice, as we'll likely cast the same actor in both roles. Otherwise, feel free to go crazy with the voice, since he doesn't really even talk in the original movie. Sounding evil, raspy and over the top might work best.