The B probably stand for Black since B-Rabbit is a black rabbit.
B-Rabbit can either Black Rabbit or Bloody Rabbit due to the tragedy, the people/humans called it B-Rabbit while Alice named him Oz because Oz's name was originate to Oswald's name. Oz was never given a name when Lacie made the two rabbit doll, so Alice gave Oz a name while the other Alice (the Intention of Abyss) used Oz to create him into a chain that can severed chains.
Racism in manga where will it stop?!
...Really?...
...Really?...
Really, June...Really?
Really (i'm a racist bastard~) [i also got logged out pf my account and forgot the pasword to get in so now im anomomus]
Also.. what does "B" stands for in B-Rabbit, is it Oz's true name, remember, Oz is a chain, and chains are to believe to be a human once when they're still in the world living, so... Is it his "living name" and the rabbit stands for his personality to be so hyper, loving, huggable and something...? Oz is a name that was given to him by Alice and originate to Oswald's name (Glen).