The Emperor's True Sons (or The True Sons for short) are a somewhat Codex-deviant Chapter that hails from the shrine world of Tyrnyinous 5 of Segmetum Ultima (pronounced Tyr-ny-i-ous) and the Ultramarines are listed as their gene-seed sire. However, they have a dark secret, which will be covered later.
After the War of The Beast, the Imperium realised that they needed more space marines. To realise this goal the imperium created many more Space Marine Chapters. This was known as the 4th Founding and the Emperor's True Sons were one of these chapters. They were founded from the stocks of the lofty Ultramarine's geneseed. As the fledgling chapter needed a command structure the Ultramarines sent Sergeant Lytros, a rather vocal call for change within the chapter and the higher ranks were keen to get rid of him and any other marines who shared his beliefs.
The 57 marines of the newly formed Beta Chapter (as they had been designated). They were given the Feral World of Tyrnyinous 5 as a recruiting world and 2 Strike Cruisers to carry their chapter to war. Their first conflict was with the Orks of Tyrnyinous 3 after they had recruited 150 initiates (at relatively lax standards for space marines and instead trained them intensely, something that would become the trademark way of training the chapter [Note 1]. This was due to to the chapter command deciding that 600 lower quality space marines were better than 200 normal marines. Each aspirant took mandatory psych tests to check for 'deviants').
The Chapter had several early setbacks as the Warboss was smarter than anticipated. He was only killed when 3 scouts disobeyed orders, stole a sniper rifle and killed the boss during the next battle. These unorthodox tactics proved successful and chapter command realised that having a group of veterans well trained in these types of tactics would be the best way to serve the Emperor. Due to need for more specialised training, these men would need to be trained separately to the rank and file. They became known as the Blackwatch.
Several years later, the chapter was clearing a space hulk, known as the Da Snakhead, filled with Orks who had survived the War of the Beast (though fortunately they lacked the terrifying technology of the Orks involved). The clearing went badly initially as the orks were well organised and pulled a flanking manoeuvre, until 7 space marines, 3 armed with volkinite weapons, appeared behind the ork flankers and vaporised them. They then charged in to support the True Sons, who attacked the orks with renewed vigour. While losses were moderate, the operation was considered a success, though their unexpected saviours were treated with suspicion as they wore no colours on their armour. Though they claimed to be Ultramarine successors, they gave no details on who their parent chapter was or how they came to be upon the space hulk. They were granted entry in the chapter though a narrow referendum (256 to 239 with 9 abstainments).
The 3 leaders (named Platine, Alphaeon and Omogous) all eventually reached the rank of Company Captain (of the 4th, 3rd and 5th respectively). They were all killed during a battle against an Alpha Legion-aligned army[Note 2].
The Changeling Debacle (999.M41) While preparing to assist the imperium during the 13th Black Crusade, their Chapter Master Asomv and 2 veterans of the 1st company was murdered by Chief Librarian Mycroft. When the Blackshield and 4 members of the Blackwatch attempted to apprehend Mycroft, they found him dead. Moreover, when his body was examined by an apothecary, it seemed that he had been killed before the attack on the chapter master, moreover, he was killed by Chaplain Smyte's Bolt Pistol. Then it conspired that Smyte had been murdered and his equipment stolen, his body disposed of in an incinerator, but witnessed by a chapter serf. Most surprisingly, the murderer of Smyte, was wearing Smyte's face. While Tyros pondered this he was ambushed by a serf who attempted to kill him. In the ensuring struggle Tyros turned a bolt pistol on his assailant, who was revealed to be the Tzeechian Daemon known as 'Changling'. Changeling was slain when the mysterious Lord Inquisitor Anteros Bloodshot intervened. The Inquisitor explained he had been tracking the daemon for months, following a trail of strange occurrences. In the aftermath, Tyros has taken the position of Acting Chapter Master for forseenable future
Chapter Homeworld and Fortress Monastery
The Shrine World worships the Emperor and the Primarchs as superhuman to the superhumans and that they are worthy of worship and reverence for their great skills. The world is notable for openly acknowledging the existence of the Traitor Primarchs as superhumans who were expected to be above any measure of humanity (in the psychological sense) and failing. This belief is beloved to have stemmed from the governors of the world (who are almost always Chapter Masters of the True Sons and never outside of their chapter) and their 'particular' opinion on the Emperor and the Primarchs.
The Fortress-Monastery is located somewhere in the mountains around the capital city of the planet, Tyrnopuis (pronounced Tyr-n-o-pouis), requiring express permission from the Chapter to even bring supplies in.
The Shrine of the Primarchs
The Shrine of the Primarchs is the largest cathedral on the planet and where the people come to worship the Primarchs as equals to the Emperor (collectively). The statues of the Primarchs are ordered in number order of their legions, from the 1st (The Lion), to the 20th, (Alpharious [and] Omegon). The traitor's statues are made of black marble while the loyalist's are made of white marble. The two forgotten Primarch's statues are made of gray granite and are covered by shrouds (the statues are actually based on the Emperor as all information on the Forgotten was destroyed). Each of the statue's armour is painted yearly in their legion's colours and have a plaque dedicated to who they were, what they were like and their legion's specialities. In the center of the temple there is a statue of the Emperor made of solid gold.
The Greenskins of Da Peakz
Part of the mountain ranges that surround the capital city are so wild and extreme that even Space Marines avoid the area. However, even there do Greenskins thrive. These Greenskins (who call themselves 'Da Deff Boyz of Da Peakz') are known to be particularly hardy, even for their kind. Even more usually, they are peaceful (for Greenskins) and occasionally trade through Gretchen proxies for scrap and precious gems with pelts and bones of giant apes and other mammalian creatures that inhabit the area. When questioned about why they are so peaceful, the grot(s) reply with "Da Prophet of Da Sky-dra sez dat you 'umies fightz better dan us and 'e wantz us to 'Become the Krork', whatever day are."
These Grots appear out of the blizzards in crude steam-powered 'snow crawlers' that are apparently powered by burning Orkish waste and the fungus that is created through the Ork reproductive cycle.
They follow mostly the Codex Astartes with several major deviations with the Blackwatch and tactics being the main issue as well the fact that their system is ruled by the Chapter as they consider themselves better at making decisions than normal humans. The Planetary Governors act as advisors and the chapter only steps in when there are major problems (e.g. protests for the governor's resignation) and larger building projects.
The Reclusiam of the Emperor's True Sons is unusual among Space Marines Chapters for allowing Librarians to become Chaplains, though they may not hold any permanent rank above Chaplain within the Chapter, as to prevent the spread of large amounts of Chaos corruption. This allows them to excorsise daemons and the seeds of heresy from the bodies of their battle brothers.
The Blackwatch is an elite group of Scouts (think the Deathwatch) charged with protecting the 'interests' of the chapter through... less savoury means. They can use anything from Tau Plasma Rifles to Dark Eldar poisons to carry out their missions, however, they are required to take psychic screenings from the Chief Librarian, another Librarian and a random sanctioned psyker of the Imperium after every mission.
The Blackshield is the head of the Blackwatch and the best sniper, spy, and assassin in the chapter, second in rank to only the Chief Librarian and the Chapter Master. The current Blackshield is Tyros "Wraith" Wyrath, considered one of the best of the Blackshields ever to have existed.
Lies, Deceit, and Manipulation
3 relic Volknite weapons, traditionally used Captains of the 3rd, 4th and 5th Companies.
A Stormraven Gunship with a Dark Eldar Night-Field hooked up to it, taken during the Night Terror raids of 854.M37.
2 Battle Barges and 5 Strike Cruisers
Chapter Beliefs and Culture
The Chapter's Beliefs on the Primarchs herald from their founding members of the Chapter. This was beacuse of their leader having served under a marine who had served with the Alpha Legion and the Word Bearers during the Great Crusade.
Chapter Combat Doctrine
The Chapter usually wages war in 3 parts and the chapter has time and time again defeated dangerous foes much more easily than one would expect.
First Stage - Information Gathering and Destabilisation
In the first stage of an attack, the True Sons send Blackwatch marines and, in some cases Scouts, to discover weaknesses in a world's defences, before launching covert operations against the Chapter's enemies. For example, during the Hal-ran Incursion in 837.35M a Blackwatch Fire-Team lead a guerrilla campaign against WAAAGH Gorcrak, destroying several ork Stompas, and large amounts of damage to the WAAAGH, before the rest of the Chapter engaged.
Second Stage - Orbital Supremacy and Preliminary Bombardment
Third Stage - Open Warfare and Domination
Notable Members of The Emperor's True Sons
Blackshield and acting Chapter Master.
Fauston the Deranged (Deceased)
Former Chief Librarian who tried to preform the Rubric of Ahriman and failed, creating the Tarnished Souls and the Dark Scions.
Khamasent the Dark Heir
The leader of the Chaos Marine Warband known as the Dark Scions.
The Immortally Cursed Lukefire (pronounced Lu-kef-ire)
Leader of the mercenary chapter renegades, the Tarnished Souls.
Kyon the Furious
The new Chief Librarian of the chapter following the Changeling Debacle, Kyon is known for his storm-like temper and utter loathing of anyone who treats Psykers with anything other than respect, unless they are ignorant of their curse. This is a holdover from his youth in a particularly fanatical noble household on a now lost Hive World where he was abused by those he should have been able to rely on because he was a Psyker.
Known Geneseed Flaws
There are 2 major flaws in the Chapter's Geneseed. Firstly, some members of the chapter suffer from giant or dwarfism. The giantism sufferers are noted as being stronger, taller (averaging at 8 feet and 3 inches) and are commonly more fanatical in their beliefs. They are also extremely loyal to the chapter while also being very cunning and proud. The dwarfism sufferers, on the other hand, stand (on average) 6 feet 8 inches and are more lightly built, but are more agile and can pass for human a lot easier, which is useful in the scout corps and the Blackwatch.
Some Scholars trace the flaws to the Astartes who joined the Chapter in M31, possibly due to exposure to the warp during their warp transit on the space hulk Da Snakhead before the helped the chapter cleanse the ship.
If there are any positions in this chapter that mirror existing things in the canon or this fanon wiki, know that this is probably a coincidence.