Storyline and Theories Contest #4: Xian Weapons! was a community-run canonization contest held on BZPower in 2008. Participants in the contest were asked to describe and design one of the many weapons that might be produced by the island of Xia, a place within the BIONICLE universe that was known for manufacturing weapons used throughout the Matoran universe. The contest consisted of three categories: art, description, and MOC. The art category consisted of three sub-categories: hand-drawn, computer, and other. Five winners were selected for each category (in art, two each for hand-drawn and computer and one for other). BIONICLE author Greg Farshtey accepted the functionality and visual depictions of the 15 winning entries into BIONICLE canon.
The following weapons were announced as the winners of the contest on September 15, 2008:
Each entry included a summary which described the functionality and backstory of the weapon within the BIONICLE storyline. According to Greg Farshtey, he looked over the winning entries mainly for the weapons, how they worked, and how they were made, and those are the only parts are to be considered canon (not the backstory given alongside them). Greg also later remarked that the name of the Nihu-Motara Energy Siphon Blade was never canonized, only its functionality.