The Light Year has a short, blue handle with a silver spike in its pommel. Its guard is a slightly curved, black rectangle with gold edges and two semi-circular notches on its underside. The main blade is rather short and is pale turquoise at its base and slowly shifts to pale yellow as it get closer to the arrowhead-shaped tip. The tip of the blade also has three short, black spikes on it. There is an additional, bronze blade with gold edges connected to either side of the main blade, though they are not attached to each other. The tips of these blades slant downward, and each has two circular notches taken out of its outer edge.
When Saïx enters his berserker state, the two side spikes on the tip of the Light Year's main blade become longer. The bronze side blades become larger and their positions on the claymore change. The top halves of the two blades are now connected, forming an arrowhead shape, and separate from the lower halves. The two lower halves are now present on either side of the main blade, while the combined upper halves are now present just above the tip of the main blade. The entirety of this weapon is also surrounded by a white blade with thin, yellow edges.
A lightyear is the distance light travels in one year. The distance is roughly 5,900,000,000,000 miles.
Light Year's ground combo consists of a forward dash and two slow 360° spinning slashes, followed by a leap forward and a powerful downward slash.
The aerial combo consists of a dash forward in mid-air and a 360° spinning swipe, then a fast sideways slash, followed by an upward diagonal slash and a powerful downward vertical slash.