This crabby customer is the in-game representation of a former forum-goer of rpgmaker.net: The Real Brickroad. It was his criticism of the original RMN Bros. that sparked the Talking Time Bros. series and the unofficial rivalry between the two sites. The character was originally made by SovanJedi as the final boss of RMN Bros. 2. He was used again as a bonus boss in the third and made another cameo appearance in RMN All-Stars.
As far as his connection goes with The Real Brickroad, there isn't really much of one. His presence is something of a running joke along with the whole series' poor repute. His inclusion in the World Gallery is in recognition of past errors; mistakes that were finally learned from.