A resident of the Moon. She normally occupies a very important post amongst the Moon's people, and doesn't often show herself publicly. She can tentatively be classified as a divine spirit, but her nature is neither that of a god, nor oni, nor departed soul.
She doesn't usually talk much, but this is a result of her ability. When she speaks about any particular situation, (particularly to those who are thought to be involved,) that situation will begin to proceed in its opposite way. This power is similar to that of amanojaku, but she is a divine spirit ranked far above amanojaku. Amanojaku only speak contrarily, but in her case, with her words the world acts contrarily.
Should she try to accomplish something, it will end in failure, and if something bad is occurring, she has the ability to find a solution. It's not as if the situation will always improve for her personally. She's truly a divine spirit whose 'words can lead to disaster', as the saying goes.
To avoid the encroachment of impurity from Junko's attack, the sages of the Moon froze the Lunar Capital. At the same time, they evacuated the People of the Moon into the Dream World. The Capital within the Dream World was just like the ordinary Lunar Capital that its residents imagined. The People of the Moon residing there never doubted that it was the real thing.
However, they certainly couldn't stay cooped up in the Dream World forever. The longer a dream becomes, the more it can erode one's mind.
Thus, the sages proposed the "Lunar Capital Transfer Plan" as insurance.
The "Lunar Capital Transfer Plan" was to purify Gensokyo and build a new capital there. To 'purify' is to eliminate life and death. That is to say, they were going to annihilate all the living things on its surface. However, it wouldn't be easy. Their opponents were the youkai living in Gensokyo.
She thought that the spread of a particular urban legend in Gensokyo would make a good shortcut. Using her power, she created a secret Power Stone. That Power Stone had the power to change the world with people's words. Just by being near it, rumors (ie. urban legends) that shouldn't exist would materialize. A terrifying curio indeed.
When the urban legends began to materialize, she simply had to wait for someone to spread one particularly famous urban legend. That was the plan.
That famous urban legend was the "Apollo Project Coverup Theory." An unfounded rumor that "NASA is hiding the truth of what they saw on the Moon." That is to say: if a rumor spread that NASA was hiding information about the lunar civilization they saw, that very civilization, the Lunar Capital, would materialize in Gensokyo.
...however, this plan was no more than insurance. She wasn't totally serious about it, and none of the Moon's people wanted to move the capital to begin with. Returning to the Moon would be ideal. All the same, though, as much as they needed to fight back against Junko, they had no way of resisting her attack.
It was then that one of Gensokyo's humans arrived. She never imagined that Doremy would send a human to the Lunar Capital, but decided to test the human's power anyway. She found that they were strong indeed.
I'll place my bet on this human, she thought. If I speak the truth to them, the situation will reverse itself with them at the center. My Capital Migration Strategy will fail, but since Junko's attack will also fail, we'll break even. It doesn't matter what this human will do afterward, as long as the Lunar Capital is saved...