Fred and George Weasley
Although these two are not very big characters in the seven-book installment, they play some big roles in a few books. In Harry Potter and the Prisoner of Azkaban, the twins show Harry the Marauder's Map that they found that leads to many useful and helpful things. In Harry Potter and the Order of the Phoenix (their seventh year), the two escape Hogwarts and the new Defense Against The Dark Arts teacher, Professor Umbridge and left a fantastic fireworks show and a giant "W". The students found it amusing and use the phrase "rolling a Weasley" to describe disappointment at something and wanted to go away. Fred and George are also involved in Harry's big study group that is called D.A. (Dumbledore's Army). In the beginning of Half-Blood Prince, Ron, Hermione, and Harry, followed by Ginny, Mrs. and Mr. Weasley, visit the twins in their new joke shop. They are excited to see them and show all their new joke shop supplies. In Deathly Hallows, Fred Weasley gets killed outside the room of requirement by an explosion presumably by Augustus Rookwood, breaking the hearts of many Harry Potter fans. George gets his ear accidentally cut off by Severus Snape using Sectumsempra. George marries Angelina Johnson.