The Death Star II was the second Death Star battlestation to be constructed by the Galactic Empire. It was significantly larger than its predecessor, measuring over 160 kilometers in diameter, and was built after the destruction of the first Death Star at the Battle of Yavin. Emperor Palpatine insisted on the reconstruction of the battlestation as it was an integral part in his plan to destroy the Rebel Alliance, leaving the galaxy in the hands of the Empire.
The Death Star’s superlaser was revealed to be operational before the construction of the station was completed, surprising the Alliance attackers during the Battle of Endor. This was Emperor Palpatine’s plan all along, and it nearly led to the loss of the Rebels. The Alliance ground forces on the forest moon of Endor managed to deactivate the energy shield surrounding the battlestation, and the Rebel fleet proceeded to destroy the station from within, signifying the beginning of the downfall of the Empire.