The Keeper's beam was a powerful device controlled by The Keeper. It was not a weapon, but rather imparted knowledge to those struck by its light. It worked equally well on organic species and droids. The Keeper used this device during the Battle of The Keeper's World in 0 ABY to impart knowledge of its history and its creators to Princess Leia Organa, Luke Skywalker, C-3PO, and R2-D2.