"Life’s nothing but a drunken dream. And when you wake, you’re dead!"
Shungiku is a tall and tan man with a very aggressive look. He has a long face with narrow eyes, a wide grin, large eyebrows, and wild and spiky black hair. His hair is kept back with yellow bandanna, with the exception of loose strands framing his face. He is well-muscled and since childhood has been covered in deep scars all over his body. He is commonly seen wearing a black kimono with a flame-design hanging loosely at his elbows and wrapping around his abdomen. Notably, he carries four katana: one on each hip, one hanging horizontally behind his waist, and one hung diagonally across his back from his left shoulder.
Shungiku is a pervert, who likes to drink sake all the time. Shungiku also prefers to hang out when he should be working. He is also an avenger who killed 99 people to avenge his mother's death and act like he is okay killing them, but deep down, Shungiku felt much guilt over the deaths that he had caused; he even stated that his hands felt as heavy as lead from all the murders he committed.
He is the son of the head of a group of murderers. He had a passive attitude because his mother had always told him not to kill. His father believed it was a shame that his son was not feared by people, so he constantly beat up Shungiku. Shungiku's mother always cared for him and defended him. One night he saw his mother dying on the ground and thought that the one who killed her was his father because she always disobeyed him. He went on a murderous rampage killed everyone and everything. Later its discovered that his name is The Killer of 99 because he killed over 99 people. But Shungiku later found out that his father didn't kill his mother, but the Mushikari killed her.
When Shungiku was walking drunk, he walked right into a giant rock that Jinbei bought to train at, Shungiku got mad and sliced into pieces, which impressed Jinbei. Jinbei asked Shungiku to be his master. Later Shungiku was walking down the street with Jinbei during a patrol when the town folks start bad mouthing Shungiku and start hitting him with rocks. Jinbei refused to move away because he considered Shungiku as his teacher and refused to leave him which surprised Shungiku. Later they saw a giant cut at a bank and people were thinking that Shungiku did it but Shungiku told Jinbei that he wouldn't steal or kill.
Later in the next night, Shungiku was found wielding a bloody sword aside a sliced vault. The next day, Shungiku was taken to jail due to not telling anyone what had happen. Jinbei, who believed that Shungiku is innocent due to telling that he wouldn't steal, try to break him out. When Jinbei was in the jail, he tried to cut the wooden cell with a sword and told Shungiku that if he is innocent then is okay to break the rule, which surprised Shungiku. Shungiku asked Jinbei to give him his sword and used it to cut the wooden jail to set himself free.
While they were running away, the police found them and were about to kill Shungiku for escaping but Jinbei tried to defend Shungiku saying he wouldn't steal but then one of the police were cut by a giant mantis called a Oogatana Kamakiri - Bladed Mantis. Shungiku try to kill the bug but was slice by another cop due to wanting to avenge his friend from the past, but Jinbei stop him and told the police that his sin was in the past and now his sword is protecting them.
Jinbei went to help Shungiku to kill the bug when another Bladed Mantis came and they combined their skill to kill the Bladed Mantis and saved the town. When Jinbei see what's inside the Mantis, it was filled with gold. Shungiku explain that those Mantis were the one who were stealing golds but Jinbei question him why he didn't say anything to anyone but to Shungiku embarrassment, he reveals that he it was because of a dog chased him there and the first thing he grab was a bloody sword. Shungiku told him that no one will believe him if he told them that, but to Shungiku shock, Jinbei believed him. The two later were having drinks at a local tavern having fun and their bond grew stronger.
He was instrumental in defeating Manako of the Mushikari during their voyage to Hachijo Island. He comments after landing the final blow on his enemy that their death was not good enough for him to change his title of 'Killer of 99'.
Upon overhearing that Mugai was once the leader of the Mushikari, the group that killed his mother, Shungiku proceeds to attack Mugai relentlessly, questioning whether he was the one responsible for murdering her. It is only when Mugai expresses his disdain to fight a comrade by dropping his weapon that Shungiku comes to his senses and acknowledges their camaraderie once again.
During the fight with the two Crucifix Insects, Shungiku reveals that he regretted killing each of the 99 people in his rage to find his mother's killer and also that the reason he didn't kill his father was because he did not wish to end up like him. He also executes a new attack style called 'Compassion Slash', slicing his opponents who have the power of instant regeneration. His slashes are far faster than their ability to heal, reducing them to specks of red powder.
He is later seen assisting the rest of the Insect Magistrate against the fight with Yukimura Sanada.
Shungiku is highly skilled in the use of swords, demonstrating remarkable might since a young age. His overall might has even been shown able to pressure Mugai. While claiming to have no official training, implying that it is all self-taught and pure instinct, Shungiku skill allows him to easily slice through seemingly any target with any blade so cleanly, whether it is saw or a rusty katana, that the slices can clearly cast a reflection. His signature technique is the "Stroke of Repentance". He may also employ a sword style that makes use of three swords at the same time. Shungiku has displayed the use of both one and two sword styles. He also attained a demonic form.
He had an older brother, who he admires and wants to become just like.
While originally finding Jinbei annoying, Shungiku has since warmed-up to him thanks to his unyielding faith and loyalty. After seeing the attractive Oharu's overt affection for Jinbei, Shungiku has gained a new level of respect for the young samurai.
Shungiku and Hibachi have always been seen fighting with each other, but deep down in their hearts they care for each other like siblings do.
- Shungiku doesn't like dogs and hates being around them.