This article contains lore created collaboratively by the Blaseball community. It is just one of many Rumors that we've found in the Interdimensional Rumor Mill. You can find more Rumors about Brock Forbes at their Rumor Registry.
The Last Proselyte
Brock Forbes is rumored to have been the Mother Crab's last proselyte, a young avatar of her will, who was either given an immense power or became of interest to her due to already having immense power, and given a clear line of connection to her through which they enacted her bidding. It is unclear how they were chosen, but early reports of a young Forbes have described him as having been a great believer in her work.
Very few records exist of Brock Forbes during the period of servitude; many proselytes in history were recorded simply to walk into the Oldest Bay until their hair got wet and then some, never to return. No journalist has ever had the gall to ask them about their younger years, citing merely that "there was a look in his eyes" that set forth a deep unease at the thought of broaching the subject.
A Snuffed Out Firebrand
Reports of Forbes resurfacing do not name them speifically, but showcase a pattern of behavior that match a single individual with shifting physical descriptions, which suggests to researchers that this may in fact be Brock Forbes.
Years after dropping from the public radar, a figure was reportedly washed up on the Canton waterfront, draped in seaweed and fishing nets, coughing up a viscous black fluid, and porcupined with shrapnel wounds, broken blades, whaling harpoons, or other metal inserts depending on ineffectual eyewitness accounts. The figure rejected help from concerned onlookers, turned a corner, and vanished.
Afterwards, newpaper clippings and noise complaints mention a series of individuals drawing crowds and holding impassioned arguments or speeches about the Mother Crab. No inquiry was made about them at the time, as the crowds never grew to worrisome size and nobody was causing any trouble as a result. Inquiries made since the murder of the Crab Mother about the specifics of these gatherings have resulted in the same stonewalling behavior that journalists and investigators have faced asking about the murder itself, resulting in theorizing that the two are linked. It has been deemed unfeasible or even impossible to obtain further evidence towards or against the theory due to lack of witness testimony. The rule in Baltimore has stood firm: if you weren't there, they aren't going to tell you, and if you were, you'd know better than to bring it up.