Am I right that Deathwatch, Black Crusade and Only War
all focus on martial type characters, just dealing with different sides/Factions?
I believe so. It's been a bit since I've skimmed through the books. And, like the Star Wars series, each book is its own core-rulebook so expect to pay anywhere between $40-$60 for a new one.
(from their website)
Black Crusade is a remarkable addition to Fantasy Flight Games’s popular Warhammer 40,000 Roleplay line, offering players an entirely new perspective on the conflict between the Imperium of Man and the forces of Chaos. This groundbreaking concept delivers the unprecedented opportunity to play as a Disciple of the Dark Gods, whether as a Chaos Space Marine or a human Servant of Chaos.
In Dark Heresy, players take on the roles of Acolytes of the Inquisition, aiming to uncover and combat the enemies of mankind, be they aliens, heretics or mutants!
Deathwatch is a roleplaying game in which you take on the role of a member of the Adeptus Astartes—the devout, bio-engineered super-soldiers also known as Space Marines. After many years of exemplary service within your own chapter, you have been singled out and selected to join one of the most unique and specialized collectives of Space Marines—the Deathwatch.
Only the most exceptional candidates from the fighting forces of the Adeptus Astartes are invited to join the mysterious Deathwatch: to take on a new oath and safeguard the Imperium from the darkest of threats. You will now be called into service to hunt down and destroy hostile xenos forces, to seek out and crush the root of heresy and sedition, and to continually fight against the foul daemon menace that crawls forth hungrily from beyond the Warp. You are at the fore of Mankind's war for survival against an extremely hostile universe.
Only War is a complete, standalone Warhammer 40,000 roleplaying game experience in which players take on the roles of soldiers in the Imperial Guard, the galaxy-spanning armies of the God-Emperor. Fully compatible with FFG’s other Warhammer 40,000 Roleplay titles, this comprehensive game system explores a previously unseen side of life in the Imperium of Man.
In Rogue Trader, you can explore the universe of Warhammer 40,000 like never before. Vast fortunes await on the edges of the galaxy, if you and your fellow Explorers can muster the courage to find and claim them. Renown and riches reward the bold, but the unwary find only anonymous deaths. A Rogue Trader who can wrest profits from a dangerous universe through luck, cunning, or sheer force of will enjoys something few humans in the 41st millennium even know—a life of adventure and true freedom. Such a course, however, is often fraught with peril. Foul aliens, pernicious raiders, and even other Rogue Traders stand in your way on the path to greatness. Your wits, luck, skill, and courage will be tested to their utmost limits. To survive is to face even greater challenges—and to wield even greater power.