Zadock Sidney is Rosalind's father, the one responsible for breaking the Undead's seal in a fit of madness, dying in the process. He created the Trial-series Undead Trial B in his image to protect Rosalind, possessing all his creator's memories. However, Trial B was reprogrammed by Kingston to continue to monitor the fixed Undead battle & remove potential threats before he sacrifices himself to protect Rosalind from Trial G.