First, some background history...
Since late 2002/early 2003 I have been making a series of fan-stories surrounding the BIONICLE storyline. No different than what many others do. This series is known as The Legend of Mata Zuto, and it tells my version of the BIONICLE saga for the first three years of the franchise. Mata Zuto is a Great Being who, partnered with Metru Zutra, another Great Being, created the Matoran Universe. The two beings also combined their powers to create the Great Spirit Mata Nui and the Makuta (I should point out now that in this series, there can only be one Makuta in existence at a time).
Now, to set you up...
The very beginning of the epic takes place in the region simply known as the Western Region (Influx takes place solely in this part of the Matoran Universe). Zuto Nui is a massive city that's on the Southern Continent, and this is where Mata Zuto is said to hold favor over. Here, in Zuto Nui, a Matoran named Tarus sells his inner spirit to Teridax for ultimate power. Upon doing so, his named is changed to Ma-Taru, which means "Tarus of Death", (which means he is Death). However, here is when everything changes. Over twenty Toa from Gaia Nui, a neighboring city adjacent to Zuto Nui, go after the Spirit of Death and lock his spirit into a Kanohi Mask. So basically, Ma-Taru didn't last very long in his new form. The Kanohi Mask that his spirit is trapped in is taken to the island of Mata Nui for safe-keeping. Teridax finds out the location of Zuto Nuiian spies, and quickly goes to Mata Nui along with a hypnotized Mata Zuto and hundreds of followers.
...and that's the prologue!
At this point, of course, you know hardly anything about Gaia Nui or Zuto Nui, and that's if you played Fall of the Conqueror. If you haven't, then those two names are completely new to you. That's fine, but as I said earlier, both these cities are in the Western Region. Here is a map of the area. Ignore Metru Hexi because I've changed some of that, but everything on the Southern Continent is accurate.
I hope looking at that map gave you a little insight about the locations of Zuto Nui and Gaia Nui. I would also like to point out that To Die For has another chapter added: Chapter One. The view changes from that antagonist to the protagonist: Hahli. This story takes MNOLG2 and BIONICLE: Mask of Light and mixes them together, along with sticking to the Legend of Mata Zuto storyline.
Once again I urge you to read To Die For. Even you don't play the games, this is a growing tale filled with betrayal, violence, romance, and lots of death.