Patchouli Knowledge is a very smart, anemic and asthmatic magician from the Scarlet Devil Mansion. Although she has only been a boss in one game, and playable character in three others, she is still a very popular character, showing up in many endings and is referenced quite often. She spends most of her time in the mansion's library reading and writing magic books. It seems that she's capable of very powerful magic of all kinds, using many elements in a single spell, but due to her anemia, asthma and general poor health she's often unable to recite her spells.