Yasuki Tsukioka

Yasuki Tsukioka was a Crab Clan samurai who captained a koutetsukan patrolling the Sea of Shadows. Tsukioka was eventually seduced by the Shadows and desired to take the Tetsubo of Thunder from its resting place on the island in the Osaku Route. Being Tainted, however, Tsukioka could not set foot upon the island because it was warded against the Shadowlands by the Kuni family.

Tsukioka sold a map of the Osaku Route to Yoritomo Rui, hoping that she would find the tetsubo and take it for herself, which she did. Tsukioka then ambushed Rui's ship in an attempt to take the tetsubo from her. Rui proved to be the superior sailor, however, and sank Tsukioka's boat.