Remilia Scarlet is a vampire who lives in the Scarlet Devil Mansion. She enjoys drinking a special type of tea. However, only Sakuya and Remilia know whether or not this "tea" is the same beverage that humans drink...
Charisma refers to the extraordinary disposition held by many heroes, prophets, and religious leaders that allows them to charm others and inspire devotion. In the case of Remilia, her charisma may come from the fear that vampires invoke.
If Remilia decides she wants to do something, all the residents of the Scarlet Devil Mansion get involved. Those outside of the mansion are also affected―Reimu and Marisa, in particular, have often had their hands full with a number of Remilia's whims. This speaks to the extent of her influence in Gensokyo.
Vampires are powerful, but they also have many weaknesses. It's recommended that they assume this stance to make up for them. With it, they can easily defend against any and all attacks... At least, that's how it's supposed to work. Maybe it's only effective because vampires are incredibly durable and persistent.
One of a vampire's weaknesses is sunlight. However, Remilia can endure it by using a parasol. In the world of Touhou LostWord, she also uses extremely potent sunscreen. As powerful as this defensive stance is... it can't defend against sunlight.