The Crusaders

are a military order devoted to routing out corruption, treason and heathens in Sangheili society, coming into conflict with corrupt politicians, dangerous cults, military deserters, soldiers guilty of treason, criminal syndicates, bandits, pirates and those who would shield them. 
Crusaders have existed almost as long as Sangheili honour has, the first recorded Crusder being a former general who hunted down and killed his four treasonous bodyguards, after they attempted to assassinate him. Historical documents made it clear, the general never went after them out of revenge, but out of anger at their lack of honour. Over history, more Sangheili have undergone personal Crusades, the successful being elevated to near mythical status, the unsuccessful disappearing into obscurity. The first organized crusade was formed by a officer a millenia before the Writ of Union, He and his loyal soldiers went after deserting soldiers who joined a number of bandits, routing the entire organization. These soldiers elected to leave the military after completing their task and formed the basis of the First Crusaders. They dedicated themselves to routing out organized crime, corruption and treason within the military, and within the halls of politics. 
The Crusaders were formalised as a Military Order by the High Council, if only be a narrow margin. The Crusaders accepted this by immediately investigating for signs of corruption amongst the politicians and hunting them down and publicly executing them. The Crusaders became rightly feared as paragons of justice and righteousness, and were closely aligned with the Ascetics, whom they shared many goals with. However, when the war against the San'Shyuum came, and then ended with the Writ of Union, a schism was drawn between them. The Crusaders recognised the Writ of Union as a legal act, while the Ascetics viewed it as a betrayal of their culture. This drove a wedge between them, and when the Ascetics were outlawed, but refused to disband and continued to attack the Prophets, the Crusaders elected to fight against their former brothers in arms. While at first successful in hunting down and apprehending Ascetics and bringing them to justice, they had no idea how close the Ascetics came to them. On the darkest night of winter, during a especially violent storm, a team of just fifty Ascetics climbed the sheer cliffs surrounding the Crusaders chapter house and storm the keep. Despite attack almost three hundred Crusaders, they caught them off guard, and displayed superior martial skill and tactics. By dawn, they had trapped the last hundred warriors of the centre of the keep and prepared to move on them, when the Grand Master of the Ascetics requested parley with his opposite in the Crusaders. Former sword brothers, they came to an agreement. The Crusaders would leave the Ascetics alone, and the Asectics would not intervene on Crusader business and one another would stay out of another's way. A honour binding document and the Ascetics left into the night. While the Prophets were furious that their greatest hunters refused to go after their quarry, there was little they could do to change matters. The bad blood between the two orders still exists to this day, but neither will break the centuries old Writ of Honour. 
The Crusaders are very particular in choosing their inductees. Sometimes great warriors may try to join, but that is not enough, and some times zealous warriors may try to join, and that is not enough either. When looking at recruits, Crusaders look for warriors with great martial prowess, analytical and strategic minds that are adept at finding and rooting out corruption, for warriors who are impartial, and understand the nuances of what is just, fair and honourable and those who will go to any lengths to stop this corruption. Those that fill these requirements are taken to one of their many chapter houses for training, intending to hone their mind body and soul for the trials that lay ahead. These trials are intended to flush out those who would join for profit or self advancement, and those who are not prepared for the ordeals that lay ahead. After the two year training period, they are armed and sent to serve under a officer in their order, covering a jurisdiction. They work closely with law enforcement and local politicians to find those who would betray their kin and honour, and drag them out. The strict code of honour the Crusaders follow forces them to execute any individual they find guilty of great betrayal, corruption and treachery on the spot, though they usually prefer to be sure of their actions before doing this, as execution of the wrong man is not unheard of. They investigate any possibility of corruption and travel the length and breadth of the Republic to find those that would circumvent the law. Though rare, when a Crusader arrives in a place, its not uncommon for criminals to simply surrender themselves at his feet for leniency. 
Crusaders rarely involve themselves in matters of military affair, though may work with them in search for traitors, pirates, brigands and spies. However, most Crusaders still refuse to work alongside Ascetics, or even share the immediate space with them. The centuries long peace between them has never been broken, and even though both are now ratified by the Republic, both Orders still harbour grudges and bad blood between one another. However, when the threat is great enough to Sangheili society, they will throw old grudges to the side and work together, at which point those in their path usually face ritual suicide rather than face them in battle or risk capture. 
Crusaders area of operations usually involve in working alone or in small groups within a radius of a Chapter House, which usually covers a planetary system, or in remote areas an entire sector. However, with the end of the war, and alliances with foreign empires, their Crusades may lead them out of Republic space, into the Demilitarized zone, UEG space, the space of former Covenant races such as the Kig-Yar or Jiralhanae, or beyond those borders. 
Crusaders finance themselves by seizing property off those they have captured and executed, using this to buy themselves the finest weapons and armour. They have custom fitted armour designed for them, resembling ancient heavy Sangheili armour, giving them unparalleled protection in close quarters and from gun fire. They are usually armed with a sword, and more often than not carry a fire arm, usually a plasma rifle, or in more dire circumstances, heavier armaments, such as plasma repeaters, carbines, particle beam rifles or even concussion rifles. They also have a small number of armour vehicles, Such as Revenants, Wights, Ghosts and Spectres. They also have a small number of Phantom dropships, for missions against the most powerful of criminal syndicates. They have a large supply of Asura-class Assault Shuttles, used to preform long distance Crusades and missions. They are also one of the few Military Orders to have their own capital ships, possessing a single Avenger-class Heavy Destroyer, and seven Templar-class Crovettes, used as mobile bases of operations, and to strike at the most deep rooted of corruptions.