Bionicle was the LEGO theme based on the fictional island of Mata Nui and its biomechanical heroes.
Launched in 2001, Bionicle combined buildable action figures with an extensive science-fiction mythology. Its central characters included the Toa, heroic beings who protected the island of Mata Nui and its inhabitants. The story used masks, elemental powers, tribes and recurring villains to create a connected narrative across sets and media.
Bionicle was important because it moved LEGO storytelling beyond conventional vehicles, buildings and minifigures. The sets used Technic-style construction, articulated bodies and specialized parts. The theme’s parts and characters were designed for action-figure play while still relying on LEGO-compatible building principles.
Hero Factory followed later with a different storyline and character universe. Exo-Force and Slizers were also buildable action-oriented themes, but neither was centered on Mata Nui or the Toa.