Fred Weasley was together with George Weasley the twin brother of Ron Weasley and together they made big jokes and a lot of funny stuff.
Fred and George had a fopshop which included all kind of funny stuff like candy that causes something funny. However, Voldemort's return caused that the shop needed to be temporary closed. Fred dind't like this together with George Weasley. However, George opened the shop alone together with Ron Weasley.
ORDER OF THE PHOENIX:
Fred was a member of the Order Of The Phoenix, but his exact role within the group is never revealed. Fred and George where together good in to use tools to hear enemies enc, but his the rest is not revealed. Fred and George also made a lot of jokes with their mother that he was George and that George was Fred, and she really thought that sometimes.
Due to their jokes on school, they are populair with the Hogward girls.
During a battle with Death Eaters, Fred, George and Leo where on their brooms flying, but Fred was hit by a Pai curse and fell from his Nimbus 2000. His body was not found, but apparently deceased. In reality, Fred survived and was subjected to tests to transform in a militairy soldier. Fred's transforming worked and he became one. In the season finale, he showed his new powers and used the curses to try to kill his friends, even Ron and Harry. Guus was able to hit him with a Imperio curse, but the curse later stopped and he and a group of other militairy soldiers attacked the boys. When the boys woke up, they were on a farm and apparently all the militairy soldiers left off, including Fred Weasley. He wasn't again in the series.