Have you watched “Rurouni Kenshin” anime? there are fictional character whose name is Himura Kenshin, maybe you don’t know exactly about sword which usually used by Himura Kenshin, now i will explain it to you

The Sakabatō (逆刃刀) is a type of katana that was conceived in the fictional manga and anime, Rurouni Kenshin. A common translation of the word sakabatō is “reverse-edge sword” but for the English-language dub of the Rurouni Kenshin anime it is referred to as a “reverse blade sword” and for that reason it is more commonly referred to as such. The wielder of the sakabatō was the main character of Rurouni Kenshin, Himura Kenshin.
A sakabatō is a katana with the sharpened side being the inward curved, longer side of the blade. This is the exact opposite of a standard katana which has the sharpened side as the outward curved, shorter side. The purpose of this is to make it extremely difficult for the wielder to kill their opponent. The only way for the sakabatō to cut is to rotate the hilt by 180 degrees within your hand, thus holding the sword backwards.
In the series the sakabatō is symbolic of Kenchin’s decision to leave behind his practices of the old era and to embrace a new approach during the transition, taking an oath not to kill again.
While the sword would technically be classified as a fictional sword for having not existed in history, there are some companies that have created true replicas of the sakabatō. It is a sword that existed in fiction before it existed in reality but there is speculation that it may have existed prior to Rurouni Kenshin but there is no adequate evidence to support that.