«Karakurenai» (カラクレナイ, Karakurenai?) is the curved katana used by the guild leader of «Fuurinkazan», Klein. This sword uses the «Katana» Extra Skill, which is unlocked by training the «Curved Sword» skill and sufficiently. Klein used Karakurenai up to and including the clearing of the 75th floor of Aincrad.