Nagasone Kotetsu

An uchigatana who is said to be a counterfeit of a work of Kotetsu, a swordsmith who was active during Edo era. Since he survived the intense fight of Ikedaya affair without bending or breaking when he's held by his previous master, Kondou Isami, the head commander of Shinsengumi, there's no doubt that he's a strong sword. He's blessed with great physique and has a lively personality. However, he also has a tough side when it comes to his way of life as a sword.

(Source: Touken Ranbu Wiki)