Fred Weasley and George Weasley are Gryffindor students two years older than Harry. They are twins brothers; they spend most of their time together and are often referred to as one person. They are notorious pranksters.
On April 16, 1991 they fight a mountain troll that is attacking Hermione Granger in Hogwarts. During the fight, Fred summons the Sorting Hat in which he finds the Sword of Gryffindor (canon). Dumbledore will later tell Harry that the twins are the Heir of Gryffindor (canon) but that they should not be told yet.