is Kazuki's best friend and the one that gave him his powers.
Tokiko is a 17 year old Alchemy Warrior. Her most notable feature is her scar on her face. She is brave, and fearless and has a strong hatred for homunculus. She was assigned to Gensei City to take care of the homunculus problem there. While trying to lure out a homunculus out of hiding, Muto Kazuki runs out and selfless tries to help the women he perceives is about to be killed. However in his state of trying to help her, he is stabbed through the chest. Tokiko feeling a strange attraction to his man, who, although wasn't needed, tried saving her life, without even thinking of his own decides to save his life. She inserts a Buso Renkin into his chest to bring him back alive.
She decides to stick with Kazuki to make sure he doesn't die again, as she feels it is her duty for bringing him into this dangerous world. She is amazed at how quickly he grows and at how fast he is able to come to understand his weapon. She is then assigned to Kazuki's school to help battle the growing Homunculus threat in Gensei City. While stationed there she starts to change. Because of her dramatic incident as a child, she had always been cold, and always serious. But Kazuki and his friends start to have an effect on her. They start to befriend her, and she becomes more trusting to those around her. As the story progresses she starts to fall in love with Kazuki, and decides to stay by his side at the end of the series.
Not much in known about Tokiko. All that is really ever reviled is that she was in a horrible incident when she was a child involving a Homunculus in her elementary school. Her entire school was wiped out when a Homunculus(Identity unknown) went on an eating spear when she was but a child. She was the only survivor, and was left with the scar across her face(This event left her without any memories from her early child-hood). She could have easily removed it using Alchemy, but she decided to keep it, so she would never forget what happened that day. So she would always remember her hatred for Homunculus. She then enters the Alchemy Regiment to fight the Homunculus. While in survival training she befriends a young man named Gota Nakamura(Whose parents were killed by a Homunculus when he was a baby). After this she becomes a full fledged Alchemy Warrior.
Tokiko's Buso Renkin is know as the Valkyrie Skirt. It's forms around her thigh's. It has four long scythe like blades coming out of it. She is able to call upon it very quickly, making it one of the best weapons for quick kills. It is controlled by her nerve impulses through her skin. She can use them in a variety of ways, from attacking multiple enemies at once, to focusing on multiple places on a single enemy, to cushioning her fall from high heights. She even used them to walk across the ceiling in an episode. Her weapon is made for quick kills and is at a disadvantage against enemies with strength or endurance. Tokiko makes up for this her speed, most enemies not being able to make contact with her. The name of her weapon comes from it's standby form, by the way the blades fold up. At the end of the series she is forced to give up her Kakugane, but Kazuki reassure's her, saying that the only weapon they need will be the one inside his heart.