Sith Lightsabers are a specialized type of weapon that catered to the needs and preferences of the Sith Lords. For the most part, the design differences are minimal, due to the typical modern lightsaber being based on original Sith designs. Sith lightsabers almost always utilized Synthetic lightsaber crystals as opposed to the natural crystals favored by the Jedi, a fact they considered to be a mark of superiority. Also, most Sith weapons featured an overall more aggressive design aesthetic. One of the variations on typical Sith lightsabers is the Double-bladed lightsaber. Being of Sith design, these staff-weapons are sometimes refered to as Sith lightsabers, though are not to be confused with the genuine article.
The design of these weapons changed greatly over the centuries since the founding of the Sith, sometimes featuring a standardized mold, other times being designed by individual wielders. Despite this evolution, they are almost always distinguished by their scarlet bloodshine blades, a result of the red coloration usually taken on by synth-crystals. Ultimately, the Sith wielded these weapons to mock the Jedi, a trait demonstrated by the regularly greater combat effectiveness the aggressive Sith Lords possessed.
The early Sith lightsabers were simply an improvement on the preexisting Protosabers favored by the Jedi Order. The protosabers, while leaps and bounds ahead of the original lightsaber prototypes with their unstable blades, suffered from severe issues regarding energy consumption, necessitating a belt-mounted power pack. The Sith design introduced an internal superconductor, which transferred the returning looped energy from the negative-charged flux aperture back into an internal power cell. With this modification, the power cell would only expend power when the energy loop was broken, such as when the lightsaber cut something, solving the power supply problem. The ancient Sith Lords took this miniaturization a step further with the creation of the Double-bladed lightsaber. These original saberstaffs featured sophisticated designs, effectively a single mechanism with twin emitters on either end of a standard length hilt. Later designs would be considerably simplified, with the result being a double-length hilt consisting of two separate lightsaber mechanisms. Of lesser note was the design of the Lightfoil by the Sith-aligned Mecrosa Order, which also miniaturized the standard lightsaber design to create extremely well balanced one-handed weapons. However, the defining feature of Sith lightsabers was the use of Synthetic lightsaber crystals, as opposed to the Adegan and Ilum crystals favored by the Jedi. Almost all synthetic crystals used by the Sith featured a red coloration, as a result of the forging process used to create them, though adjustments to this process and manipulations through the Force did result in crystals of different colors. Synth-crystals typically produced stronger blades than the natural Jedi crystals, and had the rare potential to "break" the blades of standard lightsabers by overloading the energy matrix and instantly burning out the opponent's weapon. However, this added strength came at the cost of blade instability, and loss of maneuverability.
Originally, Sith Lords utilized synthetic crystals due to their lack of access to the traditional sites where crystals were harvested, as these were frequented by the Jedi Order. Eventually, the use of these synth-crystals became a tradition amongst the Sith, who believed the creation of a crystal suited to one's own needs was a display of strength over the Jedi, who relied on the "untamed wilds of space" to provide. The red coloration was also a result of the forging process, though it too came to become a tradition. The aggressive crimson hue served to differentiate the Sith from their sworn enemies; the Jedi, who typically utilized softer colors, commonly blue or green. However, the bloodshine blades were not universal to all Sith, with notables such as Exar Kun continuing to favor his blue Jedi lightsaber after defecting. However, Exar was likely unaware of the custom, replaced his Jedi weapon with a red-bladed Sith saber soon afterwards. Ultimately, Sith who wielded colors other than red are usually looking to disguise their dark affiliations. Certain Sith appeared to view lightsabers as status symbols, indicating the completion of their training. During training, Sith apprentices typically utilized Sith training sabers, or were provided with Vibroblades when expected to engage in actual combat.