The Obsidian Talon is a unique combat knife, belonging to Mach.
The Obsidian Talon was created during the war. The blade is made of black obsidian and the Obsidian Equestria mercenary company was named after it. The Obsidian Talon survived the war, hidden inside the Obsidian Equestria tower. The blade was found by Razorbeak when he founded the Obsidian Equestria Talon company in the tower and later on he brought the blade to a battle involving Mach, War Machine's Steel Rangers and Clam Chowder's Applejack's Rangers.
Razorbeak used the knife to kill Brawn and gave the blade to Mach to replace his lost combat knife. Mach keeps the blade in a sheath over his shoulder after acquiring it. Ardent Vortex stole the blade during his final confrontation with Mach and tried to kill him with it, and Mach was able to recover the blade during their battle.
The Obsidian Talon is incredibly sharp, made of obsidian as opposed to steel like most combat knifes. The blade has a unique talisman embedded in it, preventing the knife from shattering or growing dull from overuse.