This is Turaga Whinado, a Turaga Galaxy. He was the Toa Galaxy of Earth and Nightmares and was key in creating the galaxy. As a Turaga, he now resides in Onu-Koro and wears the Great Kanohi Mask of Nightmares. He's armed with a Nightmare staff and wrist guns. He also has wings and can fly using them. Unknown by anyone, he is the guardian and keeper of the Great Mask of the Dead, which protects the wearer from death and allows to command beings from the black hole realm. He later gives it to a Matoran with a shattered mask, which leads to lots of problems.