Bionicle is the LEGO theme introduced in 2001 that is built around biomechanical heroes called Toa.
The theme takes place in a science-fantasy universe populated by mechanical and organic characters. The Toa are heroic figures associated with elemental powers, while Matoran communities and other groups expand the setting’s mythology. Bionicle sets were assembled mainly from specialized Technic-style parts, masks and articulated limbs rather than conventional bricks alone.
Bionicle was significant because LEGO supported it with an extensive story told through books, comics, films and online material. This made the theme more than a collection of action figures and gave fans a continuing fictional world to follow.
The theme is sometimes confused with Hero Factory, which launched later and also used buildable robotic characters. Ninjago is another story-driven LEGO theme, but its central characters are ninja and its setting is different from Bionicle’s biomechanical universe.