Ninja was a Castle subtheme from 1998 to 2000 and the first time the theme left medieval Europe, for feudal Japan. Its sets had ninja, samurai, a shogun in his stronghold and a band of robbers, with secret doors, hidden weapons and booby traps in the buildings. 6093 Flying Ninja Fortress was the largest set. The line ended in 2000 with minifigure packs. The ninja minifigures brought new headgear and weapons that LEGO used for years after. The idea came back on a much larger scale in 2011 with Ninjago, a theme of its own.
1998 LEGO Sets
1998 marked LEGO’s leap into programmable play with the launch of LEGO Mindstorms, combining motors, sensors, and code for user-built robots. LEGO also entered digital entertainment with games like LEGO Creator, LEGO Loco, and LEGO Chess. New themes included Adventurers, following Johnny Thunder’s global expeditions, and Insectoids, a sci-fi successor to Exploriens. LEGO Castle revisited classic factions such as Crusaders and Dragon Masters, reconnecting with its medieval roots while bridging into modern set design.