He can be a little selfish but like his siblings he is brave when he left with them to Jiromaru.
Ginga Densetu Anju To Jirōmaru
Saburōmaru lives together with his mother, his siblings, and Anju and her grandfather Yoshito Sawamura. One day, Yuki and Yoshito Sawamura do not return. A few days later, Yuki hobbles home in bad shape. Instead of worrying, Saburōmaru tries to get milk from his mother and gets a good slap from his brother Jirōmaru. Yuki dies of her injuries soon after.
After this Anju's uncle, Shinjirō, comes in and forces Anju to leave. Jirōmaru goes after Anju, but Saburōmaru and Koyuki are left with Tarōmaru at home.
Tarōmaru leads siblings to the place where Yoshito Sawamura and Yuki's accident occurred. There they meet Jirōmaru, Anju, and Seisaburō. Shinjirō comes in with a gun and shoots at Anju and Seisaburō. Jirōmaru jumps between Shinjiro and Anju, dying in front of Saburōmaru and the others' eyes.
19 years later Saburōmaru is still alive and Anju greets him.
- Although Saburōmaru and his siblings are around the same age as Weed's puppies, at the end of the story he and his two remaining siblings are much older. This is a mistake on Yoshi's part, probably due to the fact that the dogs in GDATJ were not originally intended to be related to Gin and his family.