Space Wolves
The Space Wolves are a Chapter of Werewolf Viking Space Marines, and are as manly as the Angry Marines are angry. Also, they like wolves, in case you couldn't figure it out from the fucking name. Extremely Nordic, very melee oriented, and perpetually drunk/feasting/chasing bitches and of course beating the living hell out of anything that they don't like, real or otherwise. They would probably get along with Kharn, who really is a nice guy, but they're still pissed off over the whole betrayal thing. Probably more amiable towards the Angry Marines, whom the Space Wolves get many good ideas for insults from. Presently, they refuse to acknowledge the Pretty Marines as an actual chapter for undisclosed reasons.
Space Wolves have a talent for rage, and it is thought by some that they pride themselves with the sheer number of enemies they have. But the Thousand Sons Chaos Legion is by and large their greatest enemy, at least that's what they think. The fact is that the rivalry began when the Space Wolves kicked the living shit out of the Thousand Sons on their home planet, which is like having your country host the Olympics and then getting last place in every event. After that Leman Russ, primarch of the Space Wolves, broke the back of Magnus the Red, who is primarch of the Thousand Sons.
This set the tone for the rest of their unhealthy relationship. The Thousand Sons do something to piss off the Space Wolves, usually some brilliant, convoluted plan, and the Space Wolves just charge and beat the living shit out of them and laugh in their faces when they find out how much work those Tzeentchies put into their plots.
Perhaps the best example can be found in the Space Wolf Omnibus, in which Ragnar Blackmane, who is basically a young Space Wolf, not only fucks over a Sorcerer, but Magnus the Red himself. The Sorcerer, Madox, is so pissed at being foiled by Ragnar that he bitches about it to other Thousand Sons, who find this hilarious, and goes around making plots, which Ragnar manages to fuck up nicely, thereby saving the galaxy. Ragnar even took the spear of his primarch and hurled it into the eye of Magnus the Red. Do note that this is as much canon as other BL anti-fluff shit.
Because of this, the Blood Ravens forge a weapon named after Ragnar, who tells them to keep their toys because he doesn't need it.
"Wolf wolf wolf wolf wolfity wolf. Wolf wolf, wolfo wolfy wolf wolf wolf. Wolf? Wolf!" -Attributed to Wolf Lord Egil Ironwolf, On the intricacies of tactical warfare.