I've never played a space marine before, but this game sounds pretty awesome
Name: Kellidan Fenrisson
Appearance: Kellidan prefers to keep his head shaven, including his eyebrows. This look can be disconcerting to some but Kellidan insists upon it, claiming that it takes no upkeep and has no chance of leaving a hair behind that might give away his presence. His nose has been broken on more than one occasion, and is slightly misshapen. His eyes are dark brown and tend to rove about the room seeking threats or targets. Kellidan is a bigger man, standing a few inches above the average space marine and is average build. Despite his size, Kellidan tends to blend in and is easily overlooked unless he calls attention to himself. He's been reprimanded on more than one occasion for missing briefings and meetings that he did attend.
Kellidan hates wearing full power armor, claiming that it hampers his movement and speed. He prefers to remain unencumbered, and wears the lighter scout marine armor whenever mission parameters allow it. He only wears a helmet when absolutely necessary, and is notorious for turning off the target finders and sense enhancement. When asked about this, he insists that he trusts his own senses more than any technological system, however advanced.
Personality: Kellidan is a bit of a contradiction: he doesn't talk much, believing that anything that doesn't need to be said is a waste of time, but prefers to be in the presence of others than alone. He usually sits quietly in the corner observing the conversation while cleaning his weapons or armor. He appreciates a good joke, but has never been known to repeat one.
Kellidan is a very practical man, and has never been known to speak of or show faith in the emperor or his saints. When asked about this, he simply states that "they are the leaders of mankind and must be followed." Kellidan puts his faith in humanity; his duty is to them first and foremost, rather then distant gods. He fights because they need someone to fight for them, and it is his duty because he has the ability. He follows his superiors unwaveringly, even when they were declared traitors. It's not that he sees them as infallible, rather because it is their duty to lead and his to follow. As a practical man, he believes that any weapon capable of destroying the enemy should be used so he doesn't understand why anyone would try to stop him and his brothers from using those weapons.
Background: Kellidan's parents died when he was young, and he was forced to rely on himself. He turned to the forests for sustenance, hunting game to stay alive. When he was chosen to become a space marine he instantly took to the way the scouts operated, and was an expert in stealth and sharpshooting. He soon became something of a legend and carried on as a scout sergeant that lead numerous successful missions. He accepted the transfer to fifth company reluctantly, and only after he was persuaded that it was his duty to help find the Grimoire of Lorgar and that his experience with stealth and infiltration would be invaluable to the mission.
Squad: Tactical. He would use a sniper rifle if one were mission appropriate
Equipment: Kellidan prefers the lighter scout armor, but will wear full power if the mission requires
Weapons: Standard load out - bolt pistol, combat knife, boltgun
I hope that works, let me know if I need to change anything