Sephiroth

Sephiroth was a mysterious warrior who devoted much of his life to enacting revenge against Klak for an unknown offence back on his homeworld.

History
Little is known about Sephiroth's life aside from the fact that he originated from a planet called Gaia. At some point, Klak visited Gaia and did something that ticked Sephiroth off, so he began pursuing the Makuta of Light across the cosmos. In doing so, he encountered several other characters and became involved in some of their ongoing schemes. Sephiroth would periodically appear to fight Klak, but neither of them were able to permanently defeat the other.

At some point, Sephiroth encountered Namah. All that is known about this confrontation is that she used her ether tendrils to disarm him from several metres away.

On one of the ocassions where Sephiroth was tracking Klak, he was suddenly captured by Blackout, who trapped both him and Klak in a virtual reality aboard Darkmount and forced them to fight the other prisoners and each other in order to escape. Sephiroth immediately attacked Vorahk-Kah, but the half-Rahkshi dodged the attack easily... too easily. Sephiroth then realized the nature of the virtual reality and refused to partake in Blackout's game. He stood on the sidelines while the other occupants killed each other until the virtual reality eventually collapsed, freeing Sephiroth and everyone else who was left.

Later, Sephiroth became interested in the Keruvim, a powerful artifact that had also caught the eye of several other characters. In Sephiroth's quest to learn more about the Keruvim, he met Akzer, who he found was was also an enemy of Klak. Once they had gotten to know each other, Akzer struck a deal with Sephiroth: if Sephiroth helped him overthrow Caiaphus as the leader of the Apprentices of Caiaphus (so that Akzer could take over the organization and turn it into his own personal army), he would help Sephiroth get the Keruvim. Sephiroth agreed to this arrangement, unaware of the fact that Akzer was planning on betraying him once he had fulfilled his end of the bargain.

Sephiroth was one of the many characters who appeared during the Battle of Mata Nui II, though the purpose of his presence there remains unclear. He immediately engaged Ta'harok in battle, but soon got bored of the fight and started to walk away. Ta'harok was infuriated by this, but he was decapitated by Blackout before he could teach Sephiroth some manners.

Meanwhile, Akzer told Klak about his plan to use Sephiroth to overthrow Caiaphus. The enraged Klak overpowered and killed the Pirate Lord, then ripped out the power core of his ship, the Mazkertis, and used it to get to the Mata Nui II to confront Sephiroth. Sephiroth openly welcomed the opportunity to fight Klak again, and violently duelled the Makuta. However, what Sephiroth was not anticipating was that Klak had grown much stronger than him in his absence, so he was forced to fake his own death in order to survive.

When Sephiroth resurfaced after his supposed death, he met Quick Billy, who he became "friends" with for a time. Afterwards, Sephiroth decided to return to Gaia, and he has not been seen since.