Battle of Prospero - Main Contingent: Known to be on Prospero at the time of the Space Wolves' assault were representatives of all of the various fellowships of the the XV Legion, the Thousand Sons, as well as the commanders of all except the 4th Fellowship.In total, it is estimated that of the Thousand Sons' known total strength of perhaps 80,000-90,000 Astartes, there were approximately 62,000 present on Prospero by judgement of after-action reports (many of which are contradictory), either within the capital city of Tizca or one of the smaller outposts elsewhere on the planet. Those fellowships and orders known to have at least a portion of their number present for the battle are recorded below:1st Fellowship, commanded by Chief Librarian Ahzek Ahriman - 9,000 Space Marines, comprising the majority of the Thousand Sons Terminator units and recently returned to full strength.2nd Fellowship, commanded by Phosis T'Kar - 7,800 Space Marines. As with most of the fellowships, this comprised a mix of unit types divided along Cult and Order lines.3rd Fellowship, commanded by Hathor Maat - 8,200 Space Marines, reinforced from recent campaigns to near full strength.5th Fellowship, commanded by Baleq Uthizzar - 6,200 Space Marines, reduced in strength after recent campaigns and with some companies operating on campaign.6th Fellowship, commanded by Khalophis - 4,000 Space Marines. It is believed that a full half of the Sixth's active strength was deployed to the sectors around Zhao-Arkhad in the galactic south.7th Fellowship, commanded by Phael Toron - 7,200 Space Marines, reduced in strength after recent campaigns and with some companies operating on campaign.8th Fellowship, commanded by Auramagma - 8,400 Space Marines, reinforced from recent campaigns to near full strength.9th Fellowship, commanded by Magistus Amon, Equerry to the Crimson King, commander of the Hidden Ones - 7,900 Space Marines, reduced in strength after recent campaigns and with some companies still active that were beyond recall range.Order of Ruin - 1,900 Space Marines and 800 Battle-Automata. It is believed that approximately half of the Order of Ruin was attached to Thousand Sons detachments operating on campaign across the galaxy or despatched in the holds of the fleet.Order of the Blind - 888 Space Marines. It is believed the entire complement of the Order had heeded Magnus' recall, arriving on Prospero via mysterious means before most other units.Order of the Jackal - 604 Space Marines, divided into detachments attached to each fellowship and contingent on crusade.Prosperine Guard - Comprising three distinct bodies; the Spireguard, Airguard and Expeditionary regiments. The Prosperine Guard regiments were outfitted to various standards, but in all cases were considered well-trained and equipped. Estimates place some 85,000 soldiers within the various barracks and training facilities of Tizca and smaller outposts scattered across Prospero at the time of the invasion.Northern Palatine Guard - This Imperial Army regiment, under the command of Colonel Katon Aphea, was deployed on the edges of the burning port of Old Tizca, which occupied the high parapets of the overlooking libraries and galleries of the Nephrate District. The Northern Palatine Guard were overran by Leman Russ and his Space Wolves in less than two solar minutes.Prosperine Spireguard - The primary Imperial Army regiment tasked with the defence of Prospero. There were some survivors of the Spireguard who were present at the Pyramid of Photep at the conclusion of the battle. Their fates remain unknown.15th Prosperine Assault Infantry - The 15th Prosperine Assault Infantry was an Imperial Army regiment under the command of Captain Sokhem Vithara. They defended the old eastern quarter of the capital city, known as Old Tizca, from the initial ground attack of the Space Wolves Legion.Prospero Assault Pioneers - An Imperial Army regiment that rallied in defence of their homeworld after the majority of their regiment was wiped out when three of their four barracks were destroyed in the initial orbital bombardment. It is assumed that they were slain to a man during the battle.Skyguard Air Command - Prospero's primary air force. They launched every squadron of their two-man, anti-gravity skimmers from their hangars to the south of Tizca. Armed with Heat Lances and Missile Pods, their disc-like aircraft duelled for supremacy with the Loyalist forces above the skies of Tizca. It is assumed that they were annihilated in the ensuing conflict.Zhao-Arkhad Taghmata - The defence forces of the autonomous Zhao-Arkhad collective of Prospero were present within their enclave in the wilderness of Prospero as part of a treaty for the supply of the Legion. They consisted mainly of various combat-automata and other mechanised units, numbering perhaps 8,000 warriors and automata. Almost none of these were present within the city of Tizca and dwelt within the subterranean Geller Barrier-screened fane.Legio Xestobiax - A full vigil of the Legio Xestobiax was stationed within the Zhao-Arkhad enclave on Prospero, comprising some twelve Titans of varying marks. As with their Zhao-Arkhad overlords, the Prospero Vigil of the Legio Xestobiax was stationed outside the city of Tizca and ensconced in vast underground bunkers in their enclave.Citizen Militia Regiments - In theory, a large percentage of the adult population of Tizca could be marshalled for war and issued weapons form the reserve armouries scattered throughout the city, creating a force of men-at-arms numbering in the millions. However, in practice such a force was of negligible strategic value considering its lack of training and effective leadership.I Helikon Legion and the Magdan FreeKorps - Both of these regiments of the Imperial Army had been re-reouted some solar months prior to the attack on Prospero to resupply and layover at Tizca awaiting pick-up and redeployment after their completion of the Tigarth Pacification. The off-world regiments were stationed in general barrack blocks on the outer edge of the city designed for such transitioning forces, and were effectively cantoned there without access to the city. These two regiments, one of mechanised infantry and the other of lightly equipped skirmishers, shared little in common save that both originated from newly Compliant worlds whose governors bore little personal loyalty to the newly appointed Warmaster Horus. In both cases, the orders that saw them transferred to Prospero at such short notice came from officers assigned to the Warmaster.