Rhombus is the first Celestial. It is the most difficult boss in the game.
Rhombus was the prototype of the Celestials, existing shortly before Chaos' birth. It does not have wings like recent Celestials. It wears a rhombus-shaped mask divided into three parts, with one light eye and one dark eye. Its hair is tied into nine ponytails with the middle one being much longer than the others, each with a hairband representing the nine basic forms of creativity. Rhombus wears a loose-fitting gray coat with colored rectangular and rhombus patterns. A banner extends out from the bottom, bearing the symbol of Rhombus's mask and triangular patterns. The sleeves are long with nine tassels that extend to the floor. The shoulders have gold and silver colored protrusions, which combine at the chest near a rhombus-shaped gem. Its pants are grey and wide-bottomed. Rhombus's hands and feet are never seen.
Rhombus's weapons are two black and white swords, one ends in a hooked T-shape and the other has several wide hooks on the edge. One can call forms into existence, and the other can give those forms a purpose.