Shinmyoumaru Sukuna

Shinmyoumaru is a descendant of Issun-Boushi, a legendary oni-slayer who managed to obtain from them a treasure called the Miracle Mallet. At first, he only used its wish-granting power to make himself bigger and to get himself a princess. He thought that since the Miracle Mallet was an oni's tool, using it recklessly would cause his own ruin. Several generations later, this particular mindset was all but gone in the minds of most inchlings. One of his descendants decided to use it again in order to live in luxury, thus breaking the taboo. However, the descendant wished for a grand castle and to rule over the inchling people. In that moment, the Shining Needle Castle appeared, and the Mallet's power ran out. Shortly after, the price of using the Mallet's power manifested itself: the entire castle turned upside-down, and they presumably descended into Gensokyo afterwards and joined the oni, also leading to the eventual forgetting of the inchlings by those living in the outside world. Afterwards, the Mallet was never spoken of again. Before the main events of Double Dealing Character, Shinmyoumaru was a normal inchling living in the Shining Needle Palace, unaware as to the history of the inchling race, as well as to the Miracle Mallet. However, Seija Kijin eventually approached her with the Mallet she had found, and asked her to use it. By falsifying the history of the inchlings and placing the blame for the race's destruction on powerful youkai, Seija was able to convince her to rally to her side, and to use the Mallet for what is ultimately Seija's own ambition.