There's alchemy mayhem in Busou Renkin (Arms Alchemy), a new anime series from the creator of Rurouni Kenshin (aka Samurai X), Nobuhiro Watsuki. It is currently being shown on TV Tokyo. It premiered early this October, and is slated to run for a twenty-six-episodes.
The original manga version was serialised in Shounen Jump, and later made into a ten-volume graphic novel set. The anime adaptation is by XEBEC, whose previous productions include D.N Angel, Love Hina, Martian Successor Nadesico and Shaman King.
The story starts as high school student Kazuki Muto wakes from a nightmare. He dreamed he had been trying to save a young girl from a gigantic, serpent-like creature, when the monster stabbed him in the chest and killed him.
Relieved that it was only a horrible dream, Kazuki carries on living life as normal. However, the same monster in his dream then really attacks him and his sister Mahiro.
From out of nowhere, the girl from his dreams appears, and defeats the monster using an alchemic weapon she calls the Valkyrie Skirt. It has several blades connected to spider-like legs that are attached to her thighs.
These alchemic weapons are referred to as busou renkin. They are created from a warrior's fighting spirit, and a kakugane, an alchemic item.