The current shrine maiden at the Hakurei Shrine, which lies on the border of Gensokyo. She once discovered flying power at the events of Embodiment of Scarlet Devil. Nothing holds her up. Back in the PC games, Reimu had to ride on Genjii, her pet turtle in order to reach the skies. The Hakurei Shrine exists to watch over the Great Boundary which ensures Gensokyo's existence, and the shrine maidens of Hakurei resolve major incidents for a living, although it happens to collapse during earthquakes. She possesses incredibly good luck and is extremely intuitive, so she's defeated multitudes of youkai she encounters. In Embodiment of Scarlet Devil, Reimu was the one who punished Remilia because Remilia released scarlet mist all over Gensokyo. She felt like it was a shrine maiden's duty to do so.
The Hakurei shrine maidens control the Great Hakurei Boundary and protect Gensokyo. In addition, she holds the power of the Hakurei Shrine maidens; they control the Great Hakurei Boundary and protect Gensokyo. If the Great Boundary were to be destroyed, either from inside or out, Gensokyo would likely not fare well. As a result, none of the youkai oppose them. Today, Gensokyo relies on the Hakurei Shrine and its shrine maidens to continue to exist as it does. However, her view on youkai is that one must hunt them without a complaint.
And it would be risky for a youkai to deafeat a shrine maiden like Reimu, many felt as if their existence was to be unmeaningful. Thus, Spell Cards were introduced. At the same time, it became possible for youkai to safely defeat the shrine maiden without worrying about the consequences. One of the Spell Cards major points is that they always prepare for the unexpected. All winners should gernerally win, leaving losers declaring rematches; all spells must admit to defeat. She is ordinary human when an incident isn't occuring. Reimu is often seen doing some shopping in the Human Village. If she catches sight of a youkai on the way, she will surely teach them a lesson. In this way, she is different from unusual humans.