The Lunar Phase has a white handle with a yellow spike set in its pommel. The base of the blade is indigo and has two small gaps in it; a square-shaped one near the base, and a triangular one closer to the center of the blade. The rest blade is comprised of three elongated, indigo diamonds connected to a very small, red diamond in the center. All three of the diamonds that make up the blade have diamond-shaped gaps in their centers. The base of the blade also attaches to this diamond, and all four pieces of the weapon are held in place by a large, grey ring.
When Saïx enters his berserker state, the base of the blade widens. The square-shaped gap is no longer present, while the triangular one in much larger. The lower half of the base also sports a vague, indigo silhouette of a heart, similar to Xemnas's Absolute Ethereal Blades. The three diamonds that make up the blade also widen. No part of the weapon is connected to the red diamond in this form, and instead their tips are held in place by the central ring. The red diamond is now kept in place by an additional pink section of the blade. The entirety of the blade is also lined by a new, white blade with pink edges.
Lunar phases are the appearances of the moon in the sky, such as a crescent moon or full moon.
The Lunar Phase's ground combo starts with a near-vertical slash upward, followed by a downward diagonal slash, and ends with a 360° spinning swipe and an upward diagonal slash.
The aerial combo consists of an upward diagonal slash, then a sideways slash, followed by a dash forward in mid-air and a 360° spinning swipe.