Reisen Udongein Inaba
A moon rabbit, she came to Gensokyo about 30 years ago to escape a war between the Earth and the Moon. Since then, she has been an apprentice to Eirin, a pet to Kaguya, and a caretaker to Tewi.
Reisen has the ability to sense and manipulate waves of all kinds, localised in her "Lunatic Red Eyes". Her signature use of this ability is manipulating brain waves through eye contact, allowing her to induce madness or hallucinations depending on the strength of her opponent's will. By increasing the frequency of brainwaves she can make a person short-tempered and irrational, or by reducing them can leave her target apathetic and depressed. Reisen can also manipulate light and sound waves to deceive the senses indirectly, from concealing the paths of her danmaku, to creating after-images of herself, to casting wide-area illusions that cause people to get lost. Finally, she is capable of releasing waves from her eyes in a destructive blast.
"Udongein" and "Inaba" are both nicknames, the first given her by Eirin and the second Kaguya; the latter is what Kaguya calls all rabbits. (Source: Wikipedia)