Armored merc with a gun
Sinclair is a guy in powered armor. He can fly. He has a gun. He can go invisible. He is designed to work alone and in that capacity, he can hold his own.
Sinclair is an old spacer from the Second Ludd War. He joined the corp early in his adult life, spent his time as a grunt, and was sent into battle as one of the guy who jumps from one ship on fire onto the enemy’s ship (also on fire). Semper Fi.
The most defining moment of his military career was aboard the Augustus Class Dreadnought, the Eigenstreik in its battle against the Ludd Capital Ship, the Rasputin around the First Rim. The Eigenstreik, having taken a critical hit in the battle to its powercore was forced to abandon within a combat situation. Sinclair and his band of brothers were ordered to “jump the void” towards the Rasputin in an attempt at forced boarding. Halfway across the void, a shot from the Eigenstreik’s Ion Cannons got lucky and ripped a hole in the ship’s rear generators. Both ships were flaming ruins in the sky. Sinclair and his fellow soldiers, as well as the enemy, were destined to die.
Only luck saved the soldier. An empty escape pod, jettisoned from the Rasputin, passed close enough to Sinclair for him to get a hold of it and ride it to the moon below: Ganymede 4. Sinclair believed himself to be the sole survivor of the battle, and he didn’t much like his chances on Ganymede 4, but upon entering the atmosphere, he saw an unknown installation and headed towards it.
The installation was peopled by deserters, though its presence had predated the battle. Basically, Haversham’s City was a trading post outside the surveillance of both the Archons and the Ludd. A haven for criminals. Sinclair regrouped, found a way off the rock, made it back to civilization, and immediately parleyed for a promotion. His new job would be to find and bring back deserters.
Since the war’s end, Sinclair has continued his job as a high end space bounty hunter. He is specialized at finding people who’ve hidden in the little pockets off of the core worlds. Since his first bountys, he’s gotten better at hunting people who are higher end than his military targets.