Heizō is Tyson's best friend and a close follower of the One-eyed Elder. He is also the eldest of his siblings. After his old pack leader dies, Heizō joins Orion's pack, becoming a good friend with him.
He is gold-yellow and white Mixed Breed.
He extremely loyal to the One-eyed Elder, and cares a great deal for his family. Heizo is easily impressed by great feats of strength.
Even though, Heizo isn't the strongest fighter he's just as brave as any solider.
Ginga Densetsu Weed: Orion
One day, while he and his family were hunting in the mountains after the volcanic explosion in Ohu, they get ambushed by Hanashiro Shinkichi and his pack. In order to protect his family, Heizō's father ordered Heizō and his younger brother Taichi, to escape and escort their mother and their sister Hiroko, back to the One-Eyed Elder's pack, while he and his sons, Junpachi and Yoshinao, hold them off.
Eventually, Heizō and Taichi watched in horror as their father and brothers get massacred by the evil dogs. As they make a brake for it, Hanashiro Shinkichi sends his two followers, Shiro and Youji, to pursue and kill them. The pursuit ends shortly after Taichi accidentally trips on his leg.
Before Heizō and Taichi had to fight the two dogs, Orion appears out of nowhere and easily defeated the two rival dogs. Heizō and his brother were so amazed that they couldn't believe their eyes. Heizo knew that it would be too dangerous to leave Orion behind, so they decide take him with them to avoid Yoshinao's pack.
They later meet up with Hiroko and their mother near a river and told them everything what happened. Since Hanashiro Shinkichi's pack was on their trail, Heizō's remaining family were forced to jump into the river, no matter how strong the current was. However, Hiroko was too scared to jump and has the rival dogs were closing in on her, Orion pushed her into the river, telling Heizō and his family that he will join them soon. After they arrived safely to their pack, Heizo and one of his friends went back to the river to search for any sign of Orion.
They later find his body near the bank of the river. Orion regains consciousness and tells Heizō that he needs to find his family. Heizō and his friend manages to convince Orion to stay in their pack by offering him a chicken wing and he eats it in front of everyone. When Orion says that he killed Hanashiro Shinkichi and avenged Heizō's family, he didn't know what to say.
He, along with the One-Eyed Elder and his pack, soon realizes that Orion is the son of Weed, the legendary leader of Ou and they tried to make him stay in the pack in order to avoid the Kurohabaki Clan, an infamous army of Kai-kens who have taken over the Ou mountains after the disaster that happened months ago. But Orion says he will be alright and leaves the pack. After he left, the One-Eyed Elder tells Heizō and his friend Tyson, to pursue Orion in case any incident happens to him.
Just as the old dog had predicted, Orion was attacked by the pit-bull terrier Ryō and his pack. Heizō knew at this rate, Orion would be killed and he jumps in front of Orion to shield Ryo's attack. In order to distract Ryo and his pack and to save Orion, he gores the pit-bull's right eye and runs away, while Tyson takes Orion to a safe place. After Heizo ran for several kilometers, Ryo's pack catches up with him and tortures him. Luckily, Izou, Shirozaru and Sasuke came to rescue him.
In the end of the battle, Heizō manages to escape and returns to Tyson and Orion. He explains to Orion that since he put his life on the line to save him and his brother and avenged his family, it was time he put his life on the line to save his. Heizō also promises Orion that he and Tyson will help him find his family. During the series, Heizō always sticks around Orion along with his friend, Tyson. He may not be the strongest fighter of the Ouu army, but he wouldn't hesitate to risk his life to protect Orion and his friends.
Ginga: The Last Wars
Later, Akame runs to indicate that the Monsoon has attacked Ōuu. Heizō starts moving immediately with the pack. They are waiting in the mountains of the Kyoto to meet Yamabiko's packs, but after two days they decide to leave as early as the pre Ōuu. Orion and Yamabiko combine forces later and arrive at Nagano to join up with Unsai. Then, United Army dog then leaves towards the Ohu.
Heizo along with others watched Unsai get carried away for treatment. Shortly after all of Monsoon's Kin are dead, he watches Akame fall unconscious due to his injures. Even though, he is revived by Daisuke and Hidetoshi; Akame needs treatment badly and is taken away.
He and the other dogs regroup and are joined by Gin, who left Daisuke's care to check on them. Feeling defeated over their losses, the army spend their days and nights cuddled together for comfort before Andy, Yamabiko, Bon and Orion leave to find Sirius.
When morning comes Heizo hears Kyoshiro chew Orion out for sending his friends away and then watches the fight by Orion and Kyoshiro even though the kishu lost. He saw Orion crying in tears saying that he stayed behind for the sake of everyone because the Ohu Army needs a true leader.