Shōseki

is the apprentice of tool maker Iō.

Background
He is an apprentice of Iō, and is helping him in his tool-making job. He often complains about hard work. One time he mistakenly sold Gameru and Kusune two ninja tools Iō created: Tsuru-Kame and Dako, to increase their budget.

Trivia

 * Shōseki's name is probably derived from, an important ingredient in gunpowder.