Hayou no Tsurugi: Shikkoku no Mashou

Laethreel, a young demon hunter, receives the mission of rescuing the princess of Gandia from the clutches of a wicked noble demon named Aju. On her journey she is accompanied by her unpredictable and blood-thristy sword, Grenki, and a sweet-talking demon named Anshu, who claims to be her ally.