The right or the left?
The right side is a bonji (Siddham script). It represents a Buddhist deity. Probably Fudō Myō-ō. If you search for bonji you can find a chart of the most commonly used bonji, and compare it with the image in the tsuba.
The left side contains the maker's name. 大森英満 (Made by Ōmori Terumitsu - signature).
This looks like a 20th century copy.