He is brown dog with black mask around his eyes with spots on sides of his muzzle, and ball patterns on his forehead.
At first, Tsuyoshi was one of Tenka's loyal followers but upon his stepson Gennai seeing Tenka's evil. He leaves Tenka to follow Gennai seeing him as a rightful male.
Tsuyoshi was a member of Tenka's pack who formed a close friendship with Gennai Ogasawara. Upon Gennai's defect, he left with his friend and two others to help in the fight against Masamune Kurohabaki.
Gennai in turn sends Shiro to spy Kurohabaki Clan, but he was taken prisoner and taken to Masamune tortured his subjects. Gennai worried when Shiro does not return, and leaves with a small army to look for him. Gennai gets the last minute to rescue Shiro and they return Tenka, but Tenka is unhappy with the failure to send a team and try to determine the Gennai to kill Shiro. However, Gennai does not agree and understand that Tenka has repeatedly failed his group to their deaths.
Tsuyoshi remains by Gennai's side as they travel to Ou to fight the invading bears. When it rains, they find the cottage and the inside Shion. In the morning, they discuss and eating together-found the boar's body from the river. The whole set of dog decides to go along with Ōu. Near the Ou, they save Rocket and Kyoshiro flow. The two recognize Gennai and they will tell them what has happened Ōu. Kyoshiro speaks ninja dogs weapon and tells Gennai is looking for Akame and Elder Koga. Gennai is reluctant to help, but agrees to Kyoshiro the instigation and command Kazuto, Minoru and Tsuyoshi searches, since then Shion after themselves.
At night Tsuyoshi runs alone and screaming that he has things for Akame. He then runs into Sirius, Rigel and Kawasemi that Unsai has sent a reconnaissance trip to Futago-Gorge east side. Tsuyoshi initially thinks Sirius is Weed, but Kawasemi correct the misunderstanding. Tsuyoshi then asks Akame's whereabouts, in which case the other dogs to explain the situation to him.
Tsuyoshi meet Mole's puppies and help to get Jerome and Koge Elder out of prison.
After Ken is saved, Tsuyoshi heads with the others to find Monsoon and begin the attack. Tysuoshi get hit by Monsoon's claws.
After Monsoon's Kin are dead, Gin's return and everyone has fallen asleep, Tsuyoshi follows Gennai who left to find Monsoon until they are met by Akakama who says that he came to find Sirius. Then, he asked him to be their guide since they are getting older they are met upon Kurokama and the others including Rocket and Rigel he welcomes them by Rocket tells them by Gin's orders they are suppose to go back.
He hears Rocket and Akakama bicker until it ends with the irish wolfhound deserting the army agreeing that Sirius should matter too and continues looking for the young akita and Monsoon following Gennai.
He and the others keep going until Rocket collapses; seeing the army disorganization Gennai asked for anyone of them to step up as a leader but when they don't the pyrenees takes over and continues to look for Monsoon and Sirius. Once there Tsuyoshi hears Sirius argue with Gennai saying that he's ruining the peace negotiations and sees Monsoon heading for Gennai.
After Monsoon leaves he hears Gennai call Akakama a male among males with great honor and when Akakama tells everyone to go after Monsoon he calms him down by saying they have a lot of time. Then, after Akakama falls asleep Tsuyoshi and the others notice a helicopter and began to assume the humans spotted Monsoon and is still in shock that Sirius wants to stay.
Tsuyoshi hears from Sirius that his purpose was to talk not to fight. With Shion still following him Rigel watches Sirius leave wanting to have a chance. Watches Gennai attack Sirius in a fit of rage for his attitude, then they all hear a cry help only to discover that it's one of the watchmen's dogs with his front paws cut off. Seeing that Sirius wants to continue he makes another move on the akita but is blocked by Rocket and giving into his anger he told Sirius to leave. Hearing Rigel's realization that only the humans could bring Monsoon down seeing that their power wasn't enough with Akakama agreeing. He also understood that the humans don't know anything about Monsoon yet; Tsuyoshi and the others begin to hear the watchmen's dogs owner's whistle and takes the fallen hunting dog back to their owners.
After Gennai leaves Bell with an important Tsuyoshi follows him as they track a helicopter hoping to lead the humans to Monsoon, until night fall and they begin to rest. They hear a scream and begin to suspect it was Sirius until the pyrenees calms them down.
When Rigel and the others return to Gennai's group his leader sees that they were unable to convince him. He sees Sirius and Zion return to the group with the bear cub surprised that the cub is still with them, hears Rigel get asked by Sirius to take Chibi back to Ohu with them. Surprised that Chibi started to speak dog language and hearing that Sirius has big hopes for the young cub. Once Rigel agrees on taking Chibi to Ohu he watches them leave with Rocket.