The Fenris System is an Imperial star system which is strategically located at the edges of both the Segmentum Obscurus and Segmentum Solar. This area of space is part of the demesne of the Space Wolves Chapter of Space Marines. The heart of the system is a blue-white star named the Wolf's Eye.
The Space Wolves maintain the vigil over this system that began many millennia ago at the close of the Horus Heresy and watch over a hundred other worlds in the immediate stellar region besides. Their demesne stretches far and wide across the scattered stars that girdle the Fenrisian star system, but it is the bitterly cold Death World of Fenris at its heart that the Space Wolves proudly call home.
Fenris serves as the Chapter's homeworld and the primary recruiting ground of the Space Wolves. It is situated in the galactic south of the Segmentum Obscurus, at the end of the Warp rift known as the Eye of Terror, from which the Forces of Chaos come forth to raid and pillage. Fenris thus maintains one of the primary bulwarks of the Imperium's defence against Chaos.
- The Primarch Departs (211.M31) - During the 197th Feast of the Emperor's Ascension on Fenris, Leman Russ gathers his closest retainers and departs for the Eye of Terror without explanation.
- The Battle for The Fang (742.M32) - Magnus the Red appears to Great Wolf Harek Ironhelm in a series of visions. Haunted by his dreams, Ironhelm becomes increasingly determined to bring the Thousand Sons to battle and finish what the Space Wolves started at Prospero more than a thousand standard years before. After receiving word that the Traitors are massing on the world of Gangava, Ironhelm launches a full attack without hesitation, leading eleven entire Great Companies into battle. Having laid his plans over hundreds of Terran years, Magnus the Red arrives on Fenris with the remaining fighting strength of his Traitor Legion. Only a single Great Company remains to defend The Fang, and Bjorn the Fell-Handed is roused from his slumber to lead a guerrilla campaign against the Traitor forces. The Thousand Sons breach the great gate of The Fang, but not before the Wolf Scout Haakon Blackwing escapes the siege to bring word to the rest of the Chapter. The Space Wolves return in force to drive their hated enemies from their homeworld. Harek Ironhelm faces Magnus in personal combat, but is struck down before mighty Bjorn banishes the Primarch in turn.
- The Plague of Unbelief (310-334.M36) - Having gathered a vast army of deluded zealots to his cause, the Apostate Cardinal, Bucharis of Gathalamor, leads his unholy crusade towards Terra during the time of turmoil known as the Plague of Unbelief. After spending many years carving a path across the galaxy, Bucharis lays siege to the Space Wolves' homeworld in order to secure a safe route towards the heart of the Imperium. Bucharis is confident that the seemingly inexhaustible forces at his disposal will soon secure him victory. He is mistaken. After a grueling three-year siege in which the Renegade forces suffer massive losses, Wolf Lord Kyrl Grimblood returns to Fenris following the conclusion of his campaign in the Eye of Terror and smashes into the rear of the Traitor lines. Caught between the impenetrable defences of The Fang and Grimblood's fleet, Bucharis' armada is forced to withdraw from Fenris, abandoning a large part of their fighting strength to their fate.
- The Ecclesiarchy Comes to Fenris (886.M41) - A delegation of Ecclesiarchy officials approaches Fenris, intending to assess the Space Wolves after hearing rumours of their worship of false gods. Logan Grimnar refuses to meet their demands when they command him to open the gates of The Fang and undergo interrogation. Foolishly, the Ecclesiarchy decide to press the matter and when their envoy Cruiser is destroyed trying to dock with The Fang the rest of the Adeptus Ministorum officials retreat, finally realising the Great Wolf is not be trifled with. However, it is not a lesson learned, and almost a standard year later the Ecclesiarchy and three Orders Militant of the Adepta Sororitas attempt to enter Fenrisian space in force. The resultant war lasts for three solar weeks before the Ecclesiarchy decides to let sleeping dogs lie and withdraws its forces.
- Battle for Midgardia (933.M41) - A Necron fleet led by Trazyn the Infinite descends upon the world of Midgardia in the Fenris System. The Necron Overlord seeks a shard of the C'tan Nyadra'zatha that slumbers in the core of the Fenrisian planet. Angered by the audacity of his foes, Logan Grimnar leads a huge force against the Necrons, turning the toxic jungles and subterranean cities of Midgardia into a bitter and brutal warzone.
The Fenris System
Fenris is a star system comprised of three worlds -- Midgardia, Fenris and Frostheim -- all of which share a long elliptical orbit around the system's single small star, the Wolf's Eye. Frostheim has one small moon, Svellgard, and Fenris itself has a single moon known as Valdrmani, or the "Wolf Moon." Like all the home star systems of the Adeptus Astartes, the Fenris System boasts significant static defences, including orbital weapons platforms, minefields and two Ramilies-class Starforts.
Only three times in the past ten thousand standard years has the Fenris System faced invasion by a force with the strength to potentially succeed at its conquest. The first was in 742.M32 by the Thousand Sons Traitor Legion during the First Battle of The Fang, the second during the Plague of Unbelief by the forces of the Apostate Cardinal Bucharis, and the third in 933.M41 in what would come to be known as the Battle for Midgardia.
- Fenris - Fenris is a Death World and the homeworld of the Space Wolves Chapter
- Valdrmani - Called "The Wolf Moon" by Fenrisians, this lifeless moon is a Dead World and the only satellite orbiting Fenris.
- Midgardia - Unlike the other planets and satellites of the Fenris System, which are mostly barren Ice Worlds, Midgardia is a highly lethal and toxic jungle-covered Death World. Because of the unnatural warm core of the planet, caused by the existence of the C'tan Shard of Nyadra'zatha imprisoned deep beneath the world's crust, the planet provides an ideal climate for a jungle to cover the majority of the planet's surface. The jungle produces toxic gases too deadly to inhale, forcing the population of the world's humans to live underground. Pallid-skinned men and women carved their settlements from the roots of the jungle above, often hanging over the magma sea below. From the jungle roots, rich nutrients in the form of viscous strands of reddish pulp are extracted, which are used in the manufacturing of medicines. Dominating the northern polar cap of the world is the Emperor's Judgement, a Nova Cannon array that, like Nova Cannons employed on Imperial warships, has four interlinked barrels.
- Frostheim - Frostheim is an Ice World that is inhabited by a human population very similar to those found on Fenris and Midgardia.
- Svellgard - The only moon orbiting Frostheim.
- Mjalnar - A Ramilies-class Starfort based in the Fenris System that is part of the Space Wolves Chapter Fleet.
- Gormenjarl - Another Ramilies-class Starfort that aids in the defence of the Fenris System and is a part of the Space Wolves Chapter Fleet.
- Champion's of Fenris - A Codex: Space Wolves Supplement (7th Edition), pp. 59-67, 69-76
- Codex: Space Wolves (7th Edition), pp. 9, 11, 13, 16-17, 20-25