Toa Hanahtu, also known as Toa Han. My favorite Bionicle, which is one reason I choose him as my Signature-Figure.
He has quite a bit of backstory. that fact is obviously closely linked to why I like him so much. Here is a brief rundown:
Toa Hanahtu used to be a Po-Matoran from an unknown island. Most of his early life is a mystery, but at some point, he was granted a Toa stone and became a Toa. An unknown amount of time later, he lost his memory, and wound up in the army of Orange and Black. (More on that later) At some point, he was discovered by a group of Toa (Which included my brother's Sig-Toa, Onvermel) Who showed Hanahtu his destiny as a Toa. Hanahtu then joined Onvermel's team as a seventh member.
Toa Hanahtu is not his original name. With his amnesia, it is lost in time. He got his name, by meeting a Pohatu (Remember about The Cave? It means multiple versions of each character inhabit our universe), but this Pohatu, being from the Rocka T3 set, thought that Toa Hanahtu was very "Handsome". Hanahtu was still very dazed at this point, and thought that was his name, but he decided to shorted it to Han. Later, on some Naming Day, he game himself the name Hanahtu.
Hanahtu has a pretty basic build, based on that of the Toa Nuva. His legs are a slightly tweaked form of the kind designed by my brother, for Onvermel. His neck area uses those Mixel joints to give his head a full range or movement. It uses a bit of custom work, but when it comes to Bionicle MOCing, I am not shy.