The Loki Sector is a region of Imperial space located to the galactic southeast of Terra that in the Segmentum Tempestus and close to the borders the Segmentum Ultima. In 989.M41, this Imperial sector was invaded by the ravaging greenskin horde of WAAAGH! Snagrod, in which one the major battles was fought upon the Space Marine Chapter Homeworld of Rynn's World, the home of the Crimson Fists Chapter. As predicted by their stoic Chapter Master Pedro Kantor, it would take many years of fighting to reconquer the worlds in the Loki Sector that were seized by WAAAGH! Snagrod. The world of Badlanding remains in Ork hands to this day.
- Badlanding - This Imperial Agri-World is located in Segmentum Ultima. It was invaded and captured by Ork Warboss Uzrog, under the orders of Snagrod, the Arch-arsonist of Charadon in 989.M41. This world is still held by the Orks.
- Rynn's World - Rynn's World is an Imperial Agri-World that is also the homeworld of the Crimson Fists Space Marines Chapter. It and the Rynnstar System of which it is a part were both named for the Imperial Reclamator Saldano Malverro Rynn who first led Imperial colonists to the system, reclaimed Rynnsworld for Mankind and settled it as another Imperial Agri-World. The planet is sparsely populated, mountainous, and devoted to intensive agriculture. Due to its distance from other Imperial worlds and its proximity to Ork-controlled space, it is somewhat isolated from the rest of Imperium, with the closest neighbouring human planet being Badlanding. The Crimson Fists' Fortress-Monastery Arx Tyrannus has stood on Rynn's World for over a thousand years since their great Battle-Barge Rutilus Tyrannus was dismantled to build it after the Crimson Fists were granted Rynn's World as their fief and ceased being a Fleet-based Chapter in 740.M40. Though serving as the Chapter's homeworld, Rynn's World is not owned as a Chapter fief by the Crimson Fists, and has its own Planetary Governor. Before a devastating invasion by Orks, the planet was protected by a formidable missile defence system, designed to deter invaders and a relatively skilled Planetary Defence Force called the Rynnsguard. Unfortunately, Rynn's World is not so far from the Ork Empire of Charadon. As the Ork empire grew, Rynn's World began to present a tempting target to Charadon's ruler, Snagrod the Arch-Arsonist. The planet was finally invaded in 989.M41 by Charadonian Orks under the orders of Snagrod. In a freak accident, the Crimson Fists' fortress-monastery was destroyed in the initial invasion by one of the Chapter's own defence missiles that went rogue and the Chapter was all but wiped out. Without the protection of the Crimson Fists, the humans of Rynn's World were quickly slain, and their settlements, with the exception of New Rynn City, the planet's capital, were completely overrun. Rynn's World was eventually liberated by the Imperium following the arrival of an Imperial Reclamation Fleet in 991.M41, although it took years of fighting to reconquer both Rynn's World and the other worlds in the Loki Sector under Ork dominion.
- Codex: Space Marines (5th Edition), pg. 29
- Codex: Orks (4th Edition), pg. 29
- Codicium Imperialis, "The Battle for Rynn's City"
- Deathwatch: Honour the Chapter (RPG), pp. 58-60
- Games Day (UK Program 1999)
- Imperial Armour - Volume Two - Space Marines and Forces of the Inquisition
- Warhammer 40,000 - Planetstrike (5th Edition)
- White Dwarf 338 (UK), "Battle for Rynn's World"
- White Dwarf 288 (UK), "Index Astartes: Bloodied Fist - The Crimson Fists Space Marine Chapter," by Andy Hoare
- White Dwarf 236 (UK), "Bloodied Fist, The Rynn's World Incident" by Andy Chambers, pp. 57-62
- White Dwarf 94 (UK), "Skirmish on Rynn's World: The Battle of Jadeberry Hill," by Rick Priestley, pp. 56-62
- Crimson Tears (Soul Drinker's Series) by Ben Counter
- Heroes of the Space Marines (Anthology), "One Hate" by Aaron Dembski-Bowden
- Legends of the Space Marines (Anthology), "The Relic" by Jonathan Green
- Space Marine Battles: Rynn's World (Novel)
- Warrior Brood (Novel)