Mata Zuto was a Great Being, so looked up to and admired that an island -- named Zuto Nui -- was named in his honor. Despite the fact that he is a central character in Emzee's continuing arcs, very little is known about his personality.
Mata Zuto and his partner, Metru Zutra, were once a single entity known as Zion. It split, and the two beings proceeded to create universes and people either by themselves or by combining their powers. Over time, Mata Zuto began to become bitter after Metru Zutra and other Great Beings forbade him to do any "tweaking" to the Matoran Race. Over millenia, the relationship between Mata Zuto and the other Great Beings would worsen. Metru Zutra stood by her partner for as long as she could before pressure from other beings (including Mata Nui) caused her to distance herself from Mata Zuto.
It was discovered that Mata Zuto was at some point, hypnotized by Worula and his powers siphoned from the Sapphire Crystal. This was probably because Mata Zuto was starting to show regret and was considering rejoining his allies in Paradise. Worula, being from Paradise himself, did not want to lose such a valuable ally.
After the attack on Death Haven, the Sakai Orb was retrieved and Spade (BZPRPG) used it to bring the fallen Great Being back to life. Mata Zuto left a riddle with Spade, detailing how to ultimately stop the Mentar (BZPRPG). After that, he teleported back to Paradise.