Eighth Brother's lightsaber

The Eighth Brother's lightsaber was a double-bladed spinning lightsaber wielded by the Jedi Hunter known as Eighth Brother, similar to other double-bladed spinning lightsabers wielded by Imperial Inquisitors.

Specifications
The weapon featured a ringed emitter which could partially detach from the cylindrical handgrip in the center, allowing the twin blades to rotate rapidly without effort from the wielder. For a Jedi hunter like an Inquisitor, this function likely served as a way to intimidate opponents, as well as deflect any form of frontal attack. However, this was also the weapon's primary weakness, as a lightsaber-wielding opponent could simply destroy the emitter itself and cut the weapon in half, as was demonstrated by Kanan Jarrus during his final duel with the Grand Inquisitor aboard the Sovereign.

The handgrip could be removed entirely from the ring-shaped emitter, allowing the Force-imbued circlet of metal to be used as a throwing disc.

It could also be used to fly, spinning in a helicopter-like motion strong enough to lift the wielder off the ground.

Additionally, the Eighth Brother's lightsaber was distinct among other double-bladed spinning lightsabers used by his fellow members of the Inquisitorius in that it had the unique ability to convert into a buzz-saw-like weapon that employed the handle while the blades were deactivated.

History
The Eighth Brother carried his lightsaber while on his assignment tracking Maul, whom he knew only as "the Shadow" on Malachor. He used it in combat against the three Rebel Jedi: Kanan Jarrus, Ezra Bridger, and Ashoka Tano, when they arrived on their mission to Malachor. Ultimately, following the deaths of the Seventh Sister and the Fifth Brother at the hands of Maul, the outnumbered Eighth Brother attempted to flee from the enemy force-wielders using his lightsaber's spinning blades to slow his descent as he leaped from the Sith temple, only for the weapon to fail as a result of damage inflicted by Jarrus earlier, casuing him to fall to his death.