GB was at first a cowardly dog, submissive and slightly selfish, but had a sense of justice. At first, he believes that you cannot survive in the world by always helping others and doing good and has quarrels with Weed, who would always want to help. Slowly, GB realizes that the world doesn't change if you don't change yourself first. GB starts to have more courage and rightfulness, but he's still afraid if situations get too bad. GB is often a pessimistic and cynical dog, doubting himself and the goodness and intentions of others. He is also known to doubt the goodness of humans, though he knows there's good and bad ones. Still, he occassionally shows his optimistic side, believing that there's always hope.

Japanese Voice for reference https://youtu.be/gu_Zbudg0b4?t=5m6s