Yashamaru is a young, fallen samurai who while stalks the shadows as the phantom thief "Karasu Tengu." Brandishing an heirloom nagamaki, he was already fights using the ancestral tengu powers he has inherited. He is even claimed to be a rival of Yoshitora Tokugawa. In addition to being a thief, he is a ruthless vigilante who will ruthlessly stop the crimes of corruption, and the rest of the uninhibited Bakufu members are like Yoshitora.
Yashamaru loathes villains who exploit the weak for financial gain. When his father was executed on false charges in the past, Yashamaru has developed a deep and unparalleled hatred for the Tokugawa Shogunate.
- His surname, Kurama, is derived from a mountain in Japan where Sōjōbō, king of the tengu, was said to live. According to legend, it is where Sōjōbō taught swordsmanship to the folk hero Ushiwakamaru, more famously known as Minamoto no Yoshitsune.
- Yashamaru shares his given name with one of the Kouga Clan ninjas in the novel The Kouga Ninja Scrolls. Yasha are a race of benevolent demons in Japanese Buddhism, and are counterparts to the malevolent rasetsu.
- While his criminal alias, Karasu Tengu, literally meaning "Crow Tengu," is derived from a breed of tengu that takes on the appearance of a crow.