Talk about being at the wrong place at the wrong time! High school student Kazuki Muto had no clue what he was in for when he rescued damsel in distress Tokiko from a monster known as a "homunculus." Disguised as humans--who actually eat humans--homunculi are malevolent creatures that affix themselves to people's brains, and once fully grown, the only thing that can annihilate them is a weapon called Buso Renkin! Follow the adventures of Kazuki after he discovers that it was actually Tokiko who saved his life by implanting a kakugane--an alchemical device that transforms into a buso renkin--to replace his heart! -- VIZ Media

During the violent upheaval of the Bakumatsu era, Hitokiri Battosai was a feared and ruthless assassin. But now that the Meiji Restoration has begun to heal the wounds of civil war, Battosai has taken up a new name...and a new calling! He is now Himura Kenshin , a rurouni wanderer who has vowed to only draw his sword to protect those in need. But not everyone is pleased with Kenshin’s new direction, and enemies from his dark past have vowed to bring him down! -- VIZ Media

One hundred and forty years ago in Kyoto, with he coming of the American "Black Ships," there arose a warrior who, felling men with his bloodstained blade, gained the name Hitokiri, manslayer! His killer blade helped close the turbulent Bakumatsu era and slashed open the progressive age known as Meiji. Then he vanished, and with the flow of years, became legend. -- VIZ Media

High school students heroic act turns into epic human vs. monster sword fight! Buso Renkin is the story of teenager Kazuki Muto, who dies trying to save a girl who was being attacked by an eerie monster. The next morning, however, Kazuki is left wondering whether it was all a dream. Lo and behold, the girl, the monster, and his death are all real! The girl, Tokiko Tsumura, was actually trying to slay the homunculus (a beast that can take the form of humans, and whose main source of food is people), but Kazuki got in her way. To revive Kazuki, Tokiko replaces his heart with a "kakugane," an alchemic device that allows him to summon a lance with which to fight the monsters. It turns out that Tokiko is a member of the Alchemist Warriors, an organization sworn to protect the world from the diabolical creatures. Soon, Kazuki joins Tokiko in her quest to terminate the sinister being that creates and controls the homunculus. With less than a week to go before the homunculus lodged in Tokiko's waist reaches her brain, Kazuki and Tokiko search for the creator of the dreaded homunculi. But little do they know that the evil genius behind the human flesh-eating monsters is an eccentric, terminally ill student at Kazuki's school!

High school students heroic act turns into epic human vs. monster sword fight! Buso Renkin is the story of teenager Kazuki Muto, who dies trying to save a girl who was being attacked by an eerie monster. The next morning, however, Kazuki is left wondering whether it was all a dream. Lo and behold, the girl, the monster, and his death are all real! The girl, Tokiko Tsumura, was actually trying to slay the homunculus (a beast that can take the form of humans, and whose main source of food is people), but Kazuki got in her way. To revive Kazuki, Tokiko replaces his heart with a "kakugane," an alchemic device that allows him to summon a lance with which to fight the monsters. It turns out that Tokiko is a member of the Alchemist Warriors, an organization sworn to protect the world from the diabolical creatures. Soon, Kazuki joins Tokiko in her quest to terminate the sinister being that creates and controls the homunculus. Kazuki's black kakugane, which powers his Buso Renkin weapon and keeps him alive, will soon advance to the point where it begins draining life from others around him. Teaming up with his partner Tokiko, Kazuki leaves on a mission to find out more about the black kakugane in hopes of keeping this from happening. Meanwhile they encounter an elite group of Alchemist Warriors that have been assigned to hunt them down and kill them!

High school students heroic act turns into epic human vs. monster sword fight! Buso Renkin is the story of teenager Kazuki Muto, who dies trying to save a girl who was being attacked by an eerie monster. The next morning, however, Kazuki is left wondering whether it was all a dream. Lo and behold, the girl, the monster, and his death are all real! The girl, Tokiko Tsumura, was actually trying to slay the homunculus (a beast that can take the form of humans, and whose main source of food is people), but Kazuki got in her way. To revive Kazuki, Tokiko replaces his heart with a "kakugane," an alchemic device that allows him to summon a lance with which to fight the monsters. It turns out that Tokiko is a member of the Alchemist Warriors, an organization sworn to protect the world from the diabolical creatures. Soon, Kazuki joins Tokiko in her quest to terminate the sinister being that creates and controls the homunculus. Upon arriving at the hidden headquarters of the League of Extraordinary Elects (the L.X.E.), the Alchemist Warriors learn of the League's plot to attack the high school. Kazuki and Tokiko immediately head over there, only to discover that the school has been surrounded by Doctor Butterfly's newly created humanoid homunculus soldiers. To the Alchemist Warriors' surprise and dismay, they find that not only are they facing Doctor Butterfly's minions, but the students of the school as well!