Ok, this is a
massive exploit that anybody can do, and it's horribly in your favor. To pull off, simply fight the first fight on hard in the Colliseum over and over (alone gets 16 BP, with party gets 8 BP). Nu stands absolutely no chance of killing you. I suggest making that battle the evil battle you see in Belthasar's Lab in the original (6 Nu, 3 of them bring you to 1 HP, the other 3 do 1 damage each).
Optionally, you could outright prevent access to the Colliseum until point x in the game.
A
movie to demonstrate how easy it would be rack up the BP. (Requires patch dated March 3)