Onepu was incredibly strong for a [Matoran] and could lift many times his weight.
Onepu's color was purple. He was captain of the Ussalry, the Onu-Koro defense force. He was champion of the Great Ussal Crab Race for the last five seasons in a row.
On Metru Nui, Onepu worked as an archivist, although he lacked patience for the work. He preferred to be out capturing Rahi rather than waiting for them to be brought in by the Vahki. He was best known for leading an expedition that discovered an intact Bohrok nest beneath Le-Metru.