Zero is the protagonist of Byakuren No Fang.
Zero is a silver Siberian Wolf. His fur was initially portrayed more silver in color, but is portrayed as bluish after the style change.
As a puppy he is playful, curious, and brave, but also a bit reckless. As grown, Zero determined and strong for a young wolf.
The wolf pup was originally born in Siberia but was shipped to a pet shop by a group of poachers. He was then bought for Makoto Yoshimura as a present from his father. His father who is a sumo wrestler had spent the price of winning on alcohol, and despite promising Makoto a Tosa puppy he bought a wolf and tried to disguise it as a Tosa, and is called Chibi or Chibisuke.
Then, they come across Unryū and his owners looking for a fight. Chibi recklessly attacks the tosa but easily gets defeated and rushed to the hospital with Uminishiki. During his stay in the hospital the doctors discover Makoto's father's ruse. Despite his father's ruse Makoto decides to keep him. One day, Chibi's mother Silver Fang shows up at Zero's new home having traveled all the way to Japan to find her son. Chibi went off with his mother but is stopped by Unryū, who kills Chibi's mother. After that day, Chibi swore revenge and trains with his owner, Makoto, to become a fighting dog in order to defeat her murderer. During another training run they are ambushed by Hirano and his german shepherd who was working on Shinnosuke Anzai's order. But with 30 kilograms of weight taking off him, Zero manages to defeat the dog with his strength impressing everyone. It was after that Makoto gave Chibi his ring name: Zero. As both of them will starting from scratch, from zero.
Together with his master, Zero travels to the old man Kenichi Furuya to get more fighting experience. After a while, he and his master enter a tournament where he has to face Unryū. Zero beats him and has won the first round. However, he knows that Unryū won't let the defeat pass by easily, so Zero starts to intensify his training. His next match was towards Benigumo, a half brother of Unryū. Zero wins this match too, but only barely.
Time passes by and Zero becomes more confident in himself. At the next tournament, he faces the half blind Tosa, Dokuganryū. Zero's pride quickly brings him into trouble in this match. Only 1 minute into the fight, Dokuganryū takes over and slams Zero to the ground. Zero quickly remembers his training and fights back. He blinds the old dog after smashing him into the bars surrounding the area. After a hard fight, Zero wins. His next match is with the dog, Kenō. This fight ends shortly after started because both of their training throws the towel in the ring. For the first time, Zero leaves a match without winning but with a new friend instead. Finally, Zero meets Unryū in the final match.
They fight long and intense and Zero is almost killed. In that moment, Zero remembers life and his mother's death and regains his energy. He defeats Unryū who dies of the injury after the match. After the recange, Zero retier from the ring and as a fighting dog with his master Makoto.