“Would you like me to extend your detention?' 'Tempting. But I think I'll pass.”

—Sir Rosings and Keefe Sencen, in Unknown

Very little is known about Sir Rosings, other than the fact that he has monitored study hall in book one. It was mentioned that he has skinny arms, and a face that always looks like he ate a lemon. It can be noted that he has given both Keefe and Sophie detention.