(References to Dieron)
Note: X and Y are coordinates (light years on XY plane) relative to Terra at (0, 0)
X: 12.19 Y: 15.02[e]
 Planetary Data
- Star Type: G3V
- Position in System: 4 (of 6)
- Time to Jump Point: 8,53 days
- Number of Satellites: 2 (Bemer, Nebulos)
- Surface Water: 54%
- Atm. Pressure: Standard (Breathable)
- Surface Gravity: 1.02
- Equatorial Temp: 27° C
- Percentage and Level of Native Life: 35%, Amphibian
 Era Specific Data
- Recharging Station: Zenith, Nadir
- District Governor: Seville Newbury, Duke of Dieron
- ComStar Facility Class: A
- ComStar Representative: Precentor Myndo Waterly
- Population: 5,284,000,000
 Planetary Garrison
 3025 to 3050
 3055 to 3062 to 3067
- Eridani Light Horse High Command
- 21st Striker Regiment
- 19th Cavalry Regiment
- 3rd Dieron Regulars
 3068 to 3070
 3069 to 3072
- - At this point in time the 2nd operating at 40% of full strength, with 100% of their equipment featuring upgraded technology.
- - At this point in time, the I Principes was at 85% of full strength, with 75% of their equipment featuring upgraded technology.
 Manufacturing Centers
- Buhallin Military Products - destroyed in 2776
- Luthien Armor Works
- Osaka Heavy Metrics
 Owner History
- 2271 - Independent World 
- 2341 - Terran Hegemony 
- 2571 - Terran Hegemony 
- 2596 - Terran Hegemony 
- 2750 - Terran Hegemony
- 2765 - Terran Hegemony 
- 2767 - Amaris Empire 
- 3025 - Draconis Combine 
- 3030 - Draconis Combine
- 3040 - Draconis Combine
- 3052 - Draconis Combine
- 3057 - Draconis Combine
- 3062 - Draconis Combine
- 3067 - Draconis Combine 
- 3068 - Word of Blake Protectorate (from February)
- 3077 - Word of Blake Protectorate 
- 3079 - Draconis Combine
- 3130 - Republic of the Sphere 
 Early History
Dieron was one of the worlds abandoned by the Terran Alliance following the Outer Reaches Rebellion and the Demarcation Declaration of 2242, but Dieron was incorporated into the Terran Hegemony within a century, becoming one of the worlds within the Lone Star Province.
 Amaris Civil War
When Stefan Amaris launched Operation APOTHESIS, his coup to assume control of the Terran Hegemony, most of his plans worked well. This was not the case with Dieron, where the efforts of the Rim Worlds Army forces failed to go according to plan, and what should have been a swift takeover became a protracted conflict.
The APOTHESIS plans called for several events to happen concurrently. After assuming control of the various Castles Brian on Dieron using acts of terrorism as cover, the Rim Worlds Republic forces on Dieron were supposed to isolate and secure the planetary HPG at 1700 hours Terran Standard Time on the 27th of December 2766 while Republican WarShip forces secured both jump points, isolated Dieron and leaving it unable to communicate with the rest of the Hegemony. Republican forces were then to aggressively target Star League Defense Force bases and facilities on Dieron, reducing any resistance before the SLDF had any idea what had happened.
The officer commanding the Republican forces on the ground on Dieron was General Tolstin Eukai, and it is unclear whether Eukai received incomplete orders or simply failed to understand them; while Captain Urgur Toch and Captain Yrorran Garcil used their WarShips to interdict the two major jump points according to the plan, Eukai hadn't ordered his troops to secure the HPG by the time the first distress calls from the jump points reached Dieron. Eukai and his forces scrambled to try and initiate their phase of the plan as soon as the distress calls arrived, seventy-five minutes late, but by then it was too late.
Despite the bulk of the SLDF being present in the Periphery attempting to deal with the Periphery Uprising there were still a substantial number of SLDF personnel present on Dieron when APOTHESIS began. Dieron was the headquarters of both a complete Military Region within the Draconis Combine and the SLDF 14th Army, leading to a substantial number of military personnel in place regardless of 14th Army deployments, and there were also large numbers of retired and reserve personnel on Dieron, as well as regular personnel on leave. As soon as the first distress called reached Dieron the planetary Governor, Paolo Varellas, and the senior military officer, Major General Annika Tellman, declared a state of emergency. While the Governor called for the population to peacefully oppose the Republicans in any way possible, General Tellman opened the four Castles Brian present on Dieron to anyone that wanted to flee the occupation. Governor Varellas also fired off a distress call via the planetary HPG to every Hegemony transmitter within a fifty light year radius, although all of the transmitters that could have received the distress call were already in Republican hands.
The swift action by Tellman and Varellas prevented the Republicans from seizing either the planetary capital or Fort Hallik, the Castle Brian that contained the 14th Army HQ. There were relatively few SLDF combat forces present on Dieron, but those forces that were present marshalled under Tellman's orders and fought a holding action against the Republican forces, which Eukai led in a relatively straightforward campaign to try and gain control of the world. With tens of thousands of people sheltering within the Castles Brian, including much of the planetary leadership, Tellman sealed the four Castles before the Republicans could gain access and settled in for a siege.
The Republican forces were able to sever the SLDF communications using a mixture of conventional and nuclear strikes against the various communications relays in place, which also prevented the SLDF from operating the local Space Defense System; in turn, the SLDF destroyed the auxiliary controls for the SDS network, preventing the Republicans from gaining control over it. Eukai easily assumed control of Dieron and the Republicans swiftly placed their own puppet rulers in place, but tens of thousands of former and serving SLDF personnel amongst the population took up arms against the Republicans, combining with the ever-present threat of the four intact Castles Brian to create perhaps the most threatening planetary resistance anywhere in the former Hegemony.
Eukai had failed at almost every objective he was given; he had failed to secure the HPG transmitter, which had subsequently been destroyed by Republican forces to prevent the SLDF calling for assistance; he failed to gain control of the SDS, failed to reduce the four Castles Brian and failed to remove the SLDF presence from Dieron. Eukai's replacement arrived on Dieron on the 10th of January, passing orders to Eukai that ordered him to report personally to Emperor Stefan Amaris; Eukai made his appearance on the 28th of January where he was publicly executed for his incompetence.
 The Jihad
The Word of Blake captured Dieron after an assault on the 4th of February 3068, occupying the world and incorporating it into the Word of Blake Protectorate. While Coordinator Theodore Kurita remained comatose following his stroke in January, his son and heir Hohiro led a task force to Dieron to try and oust the Blakists on the 16th of April, but the campaign was marked by Hohiro's capture by Blakist forces on the 18th of June, leading to the DCMS reporting Hohiro as "missing, presumed dead." However, in contrast to reports of his apparent demise, a group apparently including surviving members of the Royal Black Watch rescued Hohiro alive from a Blakist prison camp on Dieron on the 4th of January 3069.
Dieron would stay in Blakist hands for years, but during Operation SCOUR a massive allied coalition task force drawn from the DCMS and Clan Ghost Bear led the assault to recapture Dieron. The campaign began on the 8th of October 3077 and would last for several months before Dieron was free. The Voice of the Dragon news service reported that there had been a brief friendly fire exchange between Ghost Bear second line forces and elements of the Dieron Regulars - for which it claimed the Ghost Bears had apologised to Gunji-no-Kanrei Kiyomori Minamoto - but dwelled more on two actions within the campaign that highlighted the superiority of the DCMS troops within the task force. The first was the 2nd Dieron Regulars assault that secured a breach into the Fortress Dieron complex; the second more significant action was that fought by the 8th Dieron Regulars alongside the Ghost Bears' Omega Galaxy atop Mount Shanyu, where the two units fought against the Word of Blake's 2nd and 19th Militia Divisions, a battle that saw the 8th Dieron Regulars press on despite the death of Tai-sa Jerry Sims.
The Blakist forces on Dieron represented one of the largest commitments by the Word of Blake during the Jihad; in terms of ground support the Blakists had deployed a task force consisting of Protectorate Militia Divisions from Acamar, Asta, Fletcher, Liberty and Milton, along with the 2nd, 3rd, 14th, 19th and 23rd Militia Divisions. Backing up the ground forces was a substantial naval force - substantial enough that no less than ten Blakist WarShips were destroyed or captured during the campaign, more capital ship losses for the Word of Blake than any other battle of the Jihad save the battle for Terra in 3078. From their core fleet, the Word of Blake lost three vessels, the Baron-class destroyer WoBS Light of Glory, the Essex-class destroyer WoBS Dawning Horizon and the Lola III-class destroyer WoBS End of Wisdom. The Blakists also lost seven WarShips from their fleet of vessels suborned from the Free Worlds League navy: the Zechetinu-class corvettes FWLS Karelia and FWLS Tirana, the Zechetinu II-class corvette FWLS Araneida, the Agamemnon-class heavy cruiser FWLS Aineas, the Eagle-class frigates FWLS Mordred and FWLS Tristram and the Thera-class carrier FWLS Sardis - although the latter was captured rather than destroyed, and would be pressed into service by Clan Snow Raven as the renamed SRS Raven's Nest.
THe underground news agency known as Drake released what it claimed to be the combat logs kept by Star Admiral James Lankenau, the Clan Snow Raven Admiral commanding the Conqueror-class carrier CSR Ark Royal. If the logs are accurate - and it is noteworthy that the logs contain no mention of the FWLS Araneida or the WoBS Dawning Horizon - the major naval combat actions took place on the 20th of November, after the Blakist task force jumped in-system on the 19th. The logs record that the Clan forces in the system comprised the Ark Royal and two Clan Ghost Bear WarShips, the Nightlord-class CGB Ursa Major and the massive Leviathan-class CGB Leviathan. The Ark Royal reportedly suffered light damage and the Ursa Major moderate damage, but the Leviathan was evidently scuttled, as the Blakists had concentrated the fire from their WarShips and their considerable Pocket WarShip fleet on the Ghost Bear battleship.
During their retreat from Dieron the Blakists attacked the military industry on Dieron, damaging the Luthien Armor Works and Terada factories so badly that by mid-3081 the plants were considered a complete write-off that wouldn't be worth attempting to rebuild.
 Nearby Systems
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Dark Age: Republic Worlds (3130), p. 234, "Planet Profile"
- ↑ 2.0 2.1 2.2 2.3 Jihad Turning Points: Dieron, p. 5, "Dieron" (map)
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Historical: Liberation of Terra Volume 1, p. 82-83, "Fortress Dieron"
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 House Kurita (The Draconis Combine), p. 188, "Planet Guide"
- ↑ Field Manual: SLDF, p. 251, "SLDF - Terran Hegemony Military Command Map"
- ↑ 6.0 6.1 House Kurita (The Draconis Combine), p. 133, "Unit Deployment Table"
- ↑ 7.0 7.1 20 Year Update, p. 40, "Draconis Combine Deployment Table"
- ↑ 20 Year Updage, p. 70, "Com Guards Deployment Tabel"
- ↑ Objective Raids, p. 25, "Draconis Combine Deployment Table"
- ↑ Field Manual: ComStar, p. 127, "Star League Defense Force Deployment Table"
- ↑ ComStar (sourcebook), p. 84, "Com Guards Deployment Table"
- ↑ Field Manual: ComStar, p. 125, "ComGuard Deployment Table"
- ↑ 13.0 13.1 Field Manual: Updates, p. 97, "Com Guards Deployment Table"
- ↑ 14.0 14.1 14.2 Field Manual: Updates, p. 100, "Star League Defense Force Deployment Table"
- ↑ Field Manual: Updates, p. 117, "Draconis Combine Deployment Table"
- ↑ 16.0 16.1 Jihad Secrets: The Blake Documents, p. 110, "Word of Blake Mercenary Deployment"
- ↑ Field Report: DCMS, p. 9, "Dieron Regulars Regimental Status"
- ↑ Field Manual: 3085, p. 187, "RAF Deployment Table - 3085"
- ↑ Technical Readout: 3050 Upgrade, p. 154, "Rotunda Profile"
- ↑ Technical Readout: 3075, p. 172, "Turhan Profile"
- ↑ Technical Readout: 3075, p. 210, "K-3N-KR4 Kiso"
- ↑ 22.0 22.1 Handbook: House Marik, p. 16, "Free Worlds League Founding "
- ↑ 23.0 23.1 Handbook: House Steiner, p. 13, "Lyran Commonwealth Founding "
- ↑ Handbook: House Steiner, p. 25, "Lyran Commonwealth after Age of War "
- ↑ 25.0 25.1 Historical: Reunification War, p. 159, "Inner Sphere - 2596"
- ↑ Historical: Liberation of Terra Volume 1, p. 11, "Inner Sphere - 2765"
- ↑ 27.0 27.1 Jihad: Final Reckoning, p. 45, "The Jihad In Review"
- ↑ 28.0 28.1 28.2 Jihad: Final Reckoning, p. 58, "The Jihad in Review"
- ↑ Field Report: DCMS, p. 21, "Draconis Combine Mustered Soldiery Deployment Map - August 3079"
- ↑ Map of the Inner Sphere 3130
- ↑ Jihad: Final Reckoning, p. 46, "The Jihad In Review"
- ↑ Jihad Hot Spots: Terra, p. 34-35, "Official Update 4"
- ↑ Jihad: Final Reckoning, p. 127, "Word Of Blake Militia Divisions"
- ↑ 34.0 34.1 Jihad: Final Reckoning, p. 128, "Original Word Of Blake Fleet"
- ↑ 35.0 35.1 Jihad Hot Spots: Terra, p. 68, "Flight of the Raven"
- ↑ Jihad: Final Reckoning, p. 107, "Draconis Combine"
- 20 Year Update
- ComStar (sourcebook)
- Dark Age: Republic Worlds (3130)
- Field Manual: 3085
- Field Manual: ComStar
- Field Manual: SLDF
- Field Manual: Updates
- Field Report: DCMS
- Handbook: House Marik
- Handbook: House Steiner
- Historical: Liberation of Terra Volume 1
- Historical: Reunification War
- House Kurita (The Draconis Combine)
- Jihad: Final Reckoning
- Jihad Hot Spots: Terra
- Jihad Secrets: The Blake Documents
- Jihad Turning Points: Dieron
- Map of the Inner Sphere 3130
- Objective Raids
- Technical Readout: 3039
- Technical Readout: 3075