User blog comment:Echo 1/BIONICLE: Chronicles Contests!!!/@comment-4434661-20110801023619/@comment-2026417-20110802174528

There isn't really any backstory in the series... all the Toa that will appear were in Toa canisters that were submerged in the endless ocean over 1,000 years ago. How all the Toa came into being and how they reached Mata Nui will be revealed later (much later) on.

But you can create a brief description (ie personality, abilities, and what not) about the character to whatever extent you wish.