Leman Russ
Not to be confused with the tank named after him.
Leman Russ (A.K.A The Great Wolf) is the primarch of the Space Wolves legion. He is a fuckhuge superhuman warrior of ungodly stubborn quality. He was such a pain in the ass that he was able to take a blow to the head from the Emperor's power fist. Granted he was knocked unconscious, but he still survived. He was an even stronger psyker than Magnus, though he'd never admit it and had no control over his abilities. General all-around badass deserving of so much respect, the Imperial Guard named their mainstay battle tank after him, so they didn't have to shit their pants every time they saw the Space Wolves.
Where the hell did he come from?
When the Primarchs were LOST *BLAM* taken away from the almighty, fucking omniscient Emperor through Tzeentchian nonsense, Leman Russ' little capsule landed on Fenris, a planet of insanity. Locals there enjoy a hard brutal life of fishing, drinking, sailing, fucking, pillaging and conquering other tribes of people for the modest little islands they all have to live on.
So it was that little baby Russ left his capsule in the polar mountain region of Asaheim. There, some monstrous female wolf found him and said to herself "I WANT!". So Russ was raised by a Thunderwolf in Spess.
Now a few years later, Russ and his wolf family were having a grand old time running around the mountains and killing the sheep and such of the humans there. Finally the king Thengir heard about the Wolf-man, and decreed he be captured and brought to his hall. So after killing Russ' mom during one of their raids, Russ was bound and gagged and dragged into the hall of the King Thengir. Of course fluff changes, so as of 7th edition we have this new bit of how he was brought to Thengir: After landing on the planet and being taken in by wolves, a hunting party stumbled across his cave, killed his wolf-mother, and Russ proceded to kill a dozen men to protect his two wolf-siblings, Freki and Geri, AFTER killing a dozen men ONE of the hunting party members realized that the two legged tan skinned person standing before them wasn't a wolf (so presumably everyone was either blind or stupid before Russ turned them around), and convinced his brethren to lower their weapons, Russ stood down, and they somehow convinced him to go with them before King Thengir.
Thengir took a wondrous interest in Russ and ordered he be educated. In a short time, Russ was trash-talking every short bastard who dared look at him the wrong way, and had become insanely good with weaponry. When Thengir finally died, all declared that Leman of the Russ become the new high King.
NOW WHAT?!
Russ conquered and took. He bartered and traded. He united the people of Asaheim under his rule. Somehow, the Emprah heard of it and realized it all had to be the work of a Primarch. So then he attended a royal banquet in the Hall of the Mountain Ki- I mean Leman Russ. The Emprah, taking a leaf out of Odin's book, disguised himself as some old geezer, then waited until the right moment to reveal his true identity. When he did Russ refused to bow down and challenged him to several contests, he ate so much the Emprah was forced to back down. Russ drank so much the Emprah was forced to back down. By now, the Emprah was fairly surprised at finally being out-done by someone else, Russ gazed upon the Emperor and challenged him combat, and so did the Emprah raise his Power Glove (specifically not a fist for some reason (because Power Glove was the name of the weapon in the early versions of the game)) into the air for all to see, and so did he then bring it down on Leman Russ's head, knocking him out in one solid hit.
Of course fluff changes and a 1-hit KO wasn't very fulfilling, so the new lore arrived: After the Emperor revealed himself Leman Russ skipped the eating and drinking contest and just challenged the Emperor to a fight. For hours they duelled, which ended when the Emperor punched Russ square in the face (debatable as to whether or not he was in his full armour and actually had his Power Fist at the time), and when Russ awoke, he laughed it off. Presumably he did a lot better this time by virtue of not being drunk. Afterwords he ended up in command of the one Space Marine legion that knows how to eat, drink, brawl and make war upon any asshole that mocks their Thunderwolf.
Russ and his Space Wolves had a goddamn good time during the Great Crusade, although it hasn't been written about so this is all we can guess. When that fag-ass Horus started whining and crying, Leman Russ and his Legion were on their way to Prospero to bring Magnus the Red to Terra for questioning. Horus intercepted the message and re-worded it to order Russ to destroy Magnus and his Thousand Sons. Russ and the Space Wolves carried out a class-10 clusterfucking on Prospero, to the point where Leman Russ himself lifted Magnus the Red over his shoulders and broke the sorcerer's back over his knee. But even so, the red bastard managed to utter one single word of power and escaped through the fucking ground. Russ was so enraged that he ordered the 13th company of Space Wolves to pursue the fleeing Thousand Sons through their pansy-ass portals.
Also it seems Russ is the reason the 2nd and 11th Legions no longer exist. So he has experience fucking up a Primarch, which is pretty goddamn manly.
Oh and empy totally gave him a spear with every single member of his original legion depicted fighting various gribbly xenos. Including Tyranids. Yup. Said spear was tossed into a certain Daemon Primarchs single eye, thereby preventing him from manifesting in reality AND resurrecting his legion. Russ totally hated this spear btw.
Post-Heresy
Although unable to return to aid the Imperium in the Battle for Terra, Russ and the Space Wolves threw themselves headfirst into the post-heresy war efforts.
One-hundred years to the day after the Emperor's internment on the Golden Throne, during a feast in the halls of the Space Wolves fortress, Russ climbed upon a table to give a speech. He was stricken with a vision, and after standing there speechless for a few minutes, he fell to one knee, issued hushed orders to his retinue, and left. He left his sons with their first Wolf Lord; Bjorn the Fell Handed, and a message.
"In the end, I will be there. For the final battle. For the Wolftime."
/tg/ theorizes that Leman Russ may return as Horo (Implying Horo isn't just one of Lemans' many, many bastard children growing up on some shithole Feudal world).
Magnus actually know where is Russ now, but he don't tell it even to his trusted sorcrer lords.
He has, in fact. A Rogue Trader picked him up and giving him a ride to Fenris, having many hilarious adventures on the way.*BLAM*
HERETICAL CROSSOVER BULLSHIT
Ulric is actually Leman Russ.
| The Primarchs of the Space Marine Legions |
|---|
 Loyalist Corvus Corax - Ferrus Manus - Jaghatai Khan Leman Russ - Lion El'Jonson - Roboute Guilliman Rogal Dorn - Sanguinius - Vulkan |
 Traitor Alpharius/Omegon - Angron - Fulgrim Horus - Konrad Curze/Night Haunter - Lorgar Magnus the Red - Mortarion - Perturabo |