Sasuke is a cowardly dog. Despite his own timid nature, he tends to criticize his friend GB. They tend to snap and mock each other at the times.Like GB at first, he saw himself as a weak one and believed that only way of surviving was obeying the big bosses. Though he seems to stay as a cowardly one throughout the series, he sometimes fights and even attacks dogs stronger than him. Sasuke is a bit sensitive and easily cries when someone is believed to be dead.

Japanese voice for reference: https://youtu.be/gu_Zbudg0b4?t=10m5s