You are (whatever name you choose-) but people at hogwarts, both students and staff know you simply as Info-chan/kun (or something along those lines) but no one knows your real name. You reside on the (blank) floor of hogwarts. in a locked room where no one can enter without your permission, or without using parsel tounge. You have a wide information network all over hogwarts, and are pretty much like info chan from yandere sim. (you choose you background, looks, but no one knows what you look or sound like since you slip notes under the floor once a request is made of you, most usually for information or hard to smuggle materials or items (ex. cigarettes, alcohol-) you usually take payments in snacks, etc.. but that depends on the price of the information, no?