The indispensable protagonist of the 'Strongest' series. According to her, Cornelia and Russell were the toughest opponents she ever faced. Her goal is simply to become the strongest. First person: I (feminine, polite) / Reimu-san (occasionally). Raised in a small hut deep in the mountains, she acquired survival skills growing up. Back then, she believed her combat skills were already the best. After being sent to the past once and honing her techniques, she became even stronger. She spares no effort to grow more powerful. She grew stronger by fighting various formidable foes, such as the aforementioned Cornelia and Russell. She acts cautiously in any battle, but usually ends up taking a 'win or bust' approach—and she wins every time. She lends a hand to anyone in trouble. Even when she's just trying to help someone, she usually ends up facing someone with terrifying power. She is a battle maniac who loves fighting strong opponents. Her personality is defined by her willingness to do anything to get stronger, though she has a kind side and tends to stick her nose into everything. She admits to herself that she is a battle junkie. Her favorite weapons are Satsujin (a katana) and Agony (a spear-like weapon). Satsujin is a black, cool-looking katana specialized for speed. Agony is a weapon specialized for pure attack power. Through long years of combat, not only her fighting skills but also her mental fortitude has toughened. She trusts whatever Marisa says. She gets confused when she sees enemies she has already defeated. This character is unrelated to the official Touhou canon.

She has no physical form. She serves as Reimu's complete support system. She handles information analysis and organization, devising strategies based on that data. She has watched over Reimu since they were children. She can often tell exactly what Reimu is thinking. She is Reimu's partner and sidekick. She is the polar opposite of the muscle-brained Reimu, but that contrast is why they work so well together. She doesn't use weapons—or rather, she can't because she lacks a physical body. She gives advice to Reimu when she's struggling, which often leads to a sudden turnaround. She doesn't participate in combat directly, but she analyzes enemy attacks and stats with speed and accuracy that even surprises her foes. Reimu trusts everything she says. Since Reimu aims to be the strongest, she believes Reimu needs the strongest supporter, so she is there. First person: I (feminine, polite).