In young age they were members of Saburō's pack but after his death they created their brotherly Trio, lead by Rocket. Some years later they joined Hōgen's army, but after meeting the Ōu Army Rocket decieded to join them and leaved his brothers.
Since living with the Ōu Army, Rocket is the fastest runner of them all and has the best sense of hearing, often hearing distant sounds the others cannot.
Rocket is an orange-coloured borzoi with white markings on his muzzle, neck, chest and legs. He has small ears with long fur on them, and has a long and thin snout. On his chest, stomach and tail, his fur is long. He has round eyes, which are coloured yellow. His eyes also have black eyeliner-like markings and small strokes over them.
Rocket is a sensible, calm and quite friendly dog.
Even while still working on the bad side, he still has sense of honor and he shows politeness towards elderly dogs and respect towards the old soldier Ben. He also doesn't want to kill if it isn't his ordered mission. He also hates it when puppies are killed.
He respects those who are ready to sacrifice themselves for others but believes such people don't exist anymore. However, his belief is proven wrong by Jerome and he has a change of attitude after meeting with the Ōu Army.
Unlike his brothers, Rocket understood Saburō's last wish and decided to live fighting for others and not only for his own survival.
Rocket is very loyal and caring towards his new comrades and always ready to help them, also sacrificing himself if needed. He dislikes his past self who always ran away but now he is ready to face death for his friends and stay with them until the end.
Though he is usually calm, Rocket once lost his temper because Rikiya's minions joined the enemy instead of defending their leader. This shows Rocket's sense of honor and that he dislikes those who give themself and their close people up just to survive.
Ginga Densetsu Weed
When Rocket was a puppy, he and his brothers Jet and Missile were abandoned by humans in the mountains in Wakayama. Fortunately for them, they were accepted in the pack lead by a Shikoku, Saburō. Later, the pack was taken over by the two Siberian Huskies Sakon and Ukon, who spent most of their time beating up the Borzoi brothers.
One day, Rocket had been beaten so badly that Saburō had interfered. Before the old leader got killed, he told the Borzoi Brothers that they have to live a life with a purpose.
Rocket, Jet and Missile later had become runners of Hōgen as they thought of him as a stronger dog. When Hōgen sends them out on a mission to capture Weed, the three bump into Ben and Cross.
However, they did not hurt them and continued their hunt. As they snatched Weed from his pack, GB and the rest of the pack hunt them down. Jerome finds Weed in the clutches of the Borzoi Brothers and fights them. On his defeat, Rocket decides to leave his brothers to join Weed to fulfill his purpose.
Rocket had a hard time gaining trust in his pack until he saved Weed and GB from falling to their deaths at the mountain. Later, when he hears from Hook and Sasuke that his brothers were killed by Hōgen, he decides to stay with Weed's pack for good to avenge his brothers' deaths.
After the battles against Hougen and the gelada baboon Shōgun, Rocket is sent out to find Weed who is on a trip with his love Koyuki. When he has finally found him, he brings the sad news of Hokkaidō's leader Hakurō was killed, Hokkaidō was conquered by the German Shepherd Viktor and Jerome is in danger. Afterwards, he successfully brings Weed and his reinforcements to Hokkaidō with the help of the Kōga dog Toshimitsu who had escaped from the gorge.
Rocket helps the wounded saluki mother Mari to get her kidnapped puppies back from the man by acting as the bait while Weed and friends free the kidnapped dogs from the cage.
Hybrid Bear Arc
Rocket was the first dog to figure out and bring news to Weed that there were more than one Hybrid Bears after witnessing a fight between a crocodile and Hybrid Polar Bear in the river. Rocket also participated in fighting alongside with Weed and his friends against the Hybrid Bears.
Rocket was originally a spy from Hōgen's group. Rocket, along with his two brothers, Jet and Missile, went to spy on Weed's pack. At one point, he told some of the pack that Hōgen has ten times more soldiers, scaring them away. He blames Carl so he won't get in trouble. The three got in a fight with Jerome, but when he was going to kill the three, Weed interrupted and told the Borzoi brothers to leave.
Rocket then realizes Weed's kindness and leaves his brothers to join him. Rocket had a hard time gaining trust from the group, especially Jerome. But, he was finally accepted by him when he saved GB and Weed from being blown off a mountain. After passing the mountains, Rocket then tells the group of a dog named Kyōshirō who might be of help to them. Rocket is from then on an important character in the series.
Ginga Densetsu Weed: Orion
The Ōu Army
He is released and meets up with the rest of the army, as well as Weed. Rocket leaps off the cliff to save Andy from falling when he attacks Kurohabaki Masamune, but although he grabs him he falls into the river below.
After the death of Masamune, Rocket is found by Orion and Weed who discovers that he's okay but just has an injured leg. Then, he falls into the river again but his pulled to shore by Gennai and reunites with Cross, Kurotora and the others.
Ginga: The Last Wars
A year has passed since the death of Kurohabaki Masamune. Upon hearing howls and roars, he is sent by Akame to investigate the cause of the noise, but is stopped when three bears appear from their hiding places. Rocket easily dodges the attacks and goes back up the hill to the others.
After many dogs are either killed or injured Gin suggests that while the others get away, he acts as a decoy but is told by Jerome and Kurotora not to do it and they will do it instead. Gin doesn't listen and charges at Monsoon, but his Battōga does nothing and Gin is easily thrown off. In a state of panic and anger, the dogs charge at the bears themselves.
Monsoon easily slashes at them all, killing Jaguar and badly injuring Rocket and the rest. Led by Monsoon, the bears carry out a full assault on the Ōu army. Rocket is heavily injured, as well as the remaining dogs. Monsoon roars in victory as the Ōu paradise falls.
After the fight, Rocket manages to escape along with Ken and Kyōshirō, the three of them sneak across the cliff face when they notice bears patrolling the grounds below. Rocket decides it is their best chance to counter attack while the bears don't notice them.
The trio travel further down stream until they make it to a small cave, close to where Gajō once stood. Inside the cave are the rotten corpses of Dodo, Buru and Shōji, having been left there after their death at the hands of Genba years ago.
Rocket climbs the walls of the cliff to assist Kyōshirō when the Kishu goes to scout the area. When the young dog is pinned down by the bears, Rocket runs in and attacks them, saving Kyōshirō and yanking him away from battle by his tail. As Bob and the bears give chase, Rocket makes a last attempt at escape by throwing himself and Kyōshirō off the cliff, where a river runs below. The bears give up their chase believing them to be dead as Bob cries over them.
Further down the stream, Ogasawara Gennai and Zion are passing by when they notice Rocket and Kyōshirō struggling in the water, and help to rescue them. The two dogs recognize Gennai and inform him of the situation.
Back to the other group, they just remembered that Ken was still in Kotobuki Valley. Akame asks if he'll be okay, because the stream could turn muddy and/or turn into a flood.
Sure enough, a flood causes a wounded Ken to be washed into the river and the Ou army go to the location to find and save him. They each keep a watchful eye on the raging river, as Kawasemi dives in to find him.
Then, Rocket and the others hear gunshots from Hidetoshi and sees the bears flee in terror, with the ordeal over seeing that Unsai critically injured. He watches Unsai get carried away for treatment after the hunters arrive Rocket follows Kawasemi and begins the finally assault on the rest of Monsoon's Kin through everyone's efforts the bears are defeated.
He and his comrades howl for victory but it's cut short by Orion and after that he hears Akame call out to Orion shocked to see him standing up.
Rocket witnesses Akame pass out but regains consciousness briefly after hearing Orion's speech he agrees that Monsoon needs to be killed. Then, when Akame loses consciousness again but is revived by Daisuke and Hidetoshi. He watches with his comrades as the kishu and Izou are taken away for treatment.
Then, he sees Sirius and Zion run after Monsoon, Rocket hears Orion asking Rigel to bring their brother back here. But, when Rigel refuses Rocket agrees saying that Sirius is an adult now and his doing what he believes in and if dies he'll have no regrets.
Some time later Rocket watches from a nearby hillside with his comrades as Daisuke and the people of the village bury their fallen allies and pays their respects.
Rocket watches with the others as the Pet Dog Squad leaves and starts to see Orion crying; Rocket says the young pup is starting to become of age. Then, he hears the promise Orion made to Akame saying they wouldn't have anymore fights until everyones recovered, With that even Rocket can admit that Orion has grown into an adult and that his sense of duty has made him stronger in a strange way. He is questioned by Kyoshiro if Orion has the making of a leader the borozi thinks he does if Orion gets rid of his recklessness and learns patience then, Rigel or Sirius couldn't rival him.
During the night Rocket and the others notice that the Kamakiri brothers went after Sirius and Cross tells Rocket to stop them; that the borozi should be able catch them with his speed. He gets right to that but soon as he begins he sees Rigel following him he tells the pup to go back but he refuses; then he comes across Bob and Orion when the black akita asks Orion where the others went he tells Orion not to be over hasty. But seeing there isn't much time to talk Rocket tells Rigel he's running ahead.
Rocket bickers with Akakama saying that their lives are more important than Sirius's but the irish wolfhound disagrees by saying that Sirius should matter too until it ends with the irish wolfhound saying he is deserting the army. The Borzoi tries to stops them to no avail. Then, along the way he teased by Gennai about not being the fastest in the army but he collapses Gennai says this is no time to rest but Rigel quickly defends him. However, doesn't want to give excuses and have the others go without him but they refuse, while Gennai leads the others to Monsoon Rocket is watched by Rigel.
Once Rocket is feeling better Rigel and him continue to follow the path of their friends hoping no one did anything reckless. Then, he and Rocket come across the forest watchmen and Bell asking her if she'd seen their friends but they hear a noise and discover to see Gennai being thrown by Monsoon. He sees his brother right in the bear's striking range until Gennai pushes him out of the way. After Sirius is knocked out by Monsoon, Rocket watches Akakama hastily attack the bear.
Rocket is relieved that Akakama has survived and then notices a helicopter in the sky but after what has just happened he still hears Sirius tell everyone that he continue his quest with Monsoon.
Rocket hears from Sirius that his purpose was to talk not to fight. With Zion still following him Rigel watches Sirius leave wanting to have a chance. He 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 blocks Gennai from making another move. 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; Rocket 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 Rocket follows him as they track a helicopter hoping to lead the humans to Monsoon knowing that he couldn't hide forever, they keep going until night fall and begin to rest. They hear a scream and begin to suspect it was Sirius until the pyrenees calms them down, and stays with Gennai as Rigel and the Kamakiri brothers leave to check on Sirius.
When Rigel and the others return to Gennai's group his leader sees that they were unable to convince him. Gennai tries to convince Rocket to return to Ohu but he didn't want to leave empty handed the pyrenees agrees with Rocket's decesion. He tells Gennai that he is prepared for the worst if Monsoon comes. He sees Sirius and Zion return to the group with the bear cub, Rocket hears Rigel get asked by Sirius to take Chibi back to Ohu with them and after Gennai's bad choice of words Rigel blocks Sirius from attacking Gennai. Surprised that Chibi started to speak dog language and hearing that Sirius has big hopes for the young cub Rocket begins to wonder if this is what Sirius ment in his ideals Rigel agrees on taking Chibi to their home with Rocket but he asks why the group says it will be too risky to make it back on his own.
With that he agrees to Sirius's request seeing that he's very good at persuading but confidental warns Sirius that if anything happens to him everyone in the army will be coming after him before leaving with Rigel and Chibi.
Once Rocket and Rigel return to Ohu with Chibi and finds the cub hiding behind a rock, Rigel explains that the dogs are their friends. But seeing the whole pack come for the cub Rocket tries to tell everyone that the cub is not an enemy and yet no one listens. Kyoshiro dives in to attack Chibi but Rigel throws him away with ease surprising everyone and explains that Chibi has no connection to Monsoon and that his mother was killed by Monsoon. He was told by Sirius to bring Chibi here until the cub becomes independent to which Rocket confirms.
When he sees that Rigel words aren't enough he vouches for Chibi by saying that the cub has no relation to Monsoon and there's no reason to kill the cub. He also hears Kurotora batters Orion for his attitude. When he hears that Orion is trying to protect everyone in Ohu Kuro says that he doesn't need protecting from him. He also sees Orion pointing his bamboo stick at the kai ken convincing the pup to attack him but is stopped by Jerome and watches in horror as Orion almost attacks the shepard. He watches Kyoshiro give Orion a beat crying in tears and Mel restrains him but soon the tears turn into laughter as everyone runs back up the hill.