Koharu (a Touhou LW original) refers to calm, warm weather with clear skies at the start of winter. This is an apt temperament for Shinmyoumaru, a descendant of the inchlings who hid great power. Shinmyoumaru is endowed with Metal Phase, since she can use the Miracle Mallet, and Star Essence, as she is a mischievous child. The cold and silent Metal Phase resists Earth Phase, because earth bears metal, but it is weak to Fire Phase, because fire refines metal. The diverse and uncooperative Star Essence resists the cooperative and indecisive Moon Essence, but it is weak to the charming and arrogant Sun Essence. ...However, her weaknesses and resistances are reversed due to the magic of her mallet that is gradually regaining its power.

Shinmyoumaru Sukuna's ability as a descendent of the inchlings. The Miracle Mallet is a special item that can apparently only be used by inchlings. It used to belong to an oni, but the inchling hero, Issun-Boushi, claimed it for his race. This means that the mallet's magic is oni magic, which might explain why the mallet's ability is so ridiculously powerful. However, the mallet is not a convenient item that can just be used whenever one pleases, as many times as they like... It carries a price. However, it seems some of the inchlings have forgotten this over the generations. Shinmyoumaru's noble inching family traces its lineage back to the "oni-slaying" hero, Issun-Boushi. The Issun-Boushi from the fairy tale supposedly has a deep connection with the god Sukunahikona described in ancient legends. Sukunahikona is a great god who partnered with Ookuninushi to travel the land and build the nation. However, he is also an unusual god who acts like a mischievous child at times. These types of gods are known as tricksters and are a staple of ancient mythology. You could even say that Seija and Shinmyoumaru are a pair of tricksters when they work together. There might not be another duo quite like them in Gensokyo...