- "For the Imperium, In the name of the Emperor, The pact we sign with blood, we declare war on the Ordo Hydra!"
- — The Illuminate Oath
The Illuminate Pact is an agreement between 7 Imperial groups, most notably, 6 different Space Marine Chapters, as well as a group of Inquisitors from an unidentified and little known Ordo Minoris. This Pact was made by this unknown Ordo for the sole purpose of combating the extreme measures utilised by the Ordo Hydra (an extremist offshoot and secret society of Inquisitors) as well as the Forces of Chaos that most Imperial forces are unaware of. These six Adeptus Astartes Chapters where chosen because they had all fought against the nefarious forces of the Ordo Hydra. Due to this unknown loyalist Ordo's secrecy within the ranks of the Holy Inquisition, it stood to reason that an external force would need to be utilised to combat their foes.
Because of this, the Illuminate Pact was born. This pact was agreed upon by all six of the Chapter Masters of each of the respective Chapters. With this pact each of the 6 Chapters then became part of this unknown Inquisition Ordo, thus allowing them to have a little more power in the Imperium as a whole.
The Illuminate Pact consists of at least 6 Space Marine Chapters who have fought against Ordo Hydra. As such, when they face against this group they must call for reinforcements from the Pact, as agreed. These Chapters are:
- Knight Wardens
- Lizard Blades
- Brothers of Blood
- Storm Marines
- Imperial Guardians
- Black Oath
Each of the 6 Chapters use various tactics against their enemies. An example of this can be seen with the Brother's of Blood and their blood-hungry rage. While this causes mass casualties to the Chapter and their enemies, the frontal assault allows for another Chapter, like the Knight Wardens, to use this distraction in order to outmanoeuvre and flank their foes, and utterly annihilate them between the hammer and anvil of the two Chapters' joint-attack.
Aside from the main group of Space Marine Chapters, there are a few possible members who have joined after the initial pact was made. While not confirmed, it is said that the following are part of the Pact.
- 28th Cadian 'Razor Dragoons'
- 45th Krieg 'Dust Mites'
- 78th Catachan 'True Devils'
- Unknown Inqusition Ordo
- Unknown Adeptus Mechanicus Order
- Order of Pure Light (Adepta Sororitas Order)
The Tenants of the Illuminate Pact were agreed upon by the six Space Marine Chapter Masters. These Tenants where made by the Chapter Masters after the pact was created. The Tenants stand as a supplementary set of rules that the Illuminate Pact Chapters must adhere to when facing the more destructive Forces of Chaos and Ordo Hydra forces. These include what tomes to use, organisation and recommended protocols to utilise.
- Organisation- The Tennnts about the force's organisation where made to make sure that they adhered to, and followed the dictats of the Codex Astartes closely. But since the pact was made with multiple Chapters, this gives them much more sway. However each of the six Chapters have at least two Battle Companies dedicated to the pact known as the 'Pact Companies'. As per the Tenants, each member of these Companies are made up of those who served in the Deathwatch or have faced Chaos time and time again. This makes them a deadly fighting force. Because of this, the Chapters can deploy 200 marines for any Illuminate Pact mission, which means that they can deploy upwards to around 1,200 Space Marines in total to fight.
- Equipment - Due to the nature of the Illuminate Pact it is required that each of the Chapters must utilise specialist gear. This includes the specialised weapons that the Astartes have used during their tenure in the Deathwatch to fight the various xenos, which makes them much more effect and deadlier than the standard equipped Space Marine.
- Command - Following the Codex, each Company is lead by a Force Commander, but following the Tenants, the Pact Companies are usually lead by a high ranking member, such as a Watch Commander or Veteran Sergeant, who led either a Kill-team or larger strike forces during their tenure with the Deathwatch.
- Secrecy - As per the primary rules of the Tenants, secrecy and operational security is vital and of the utmost importance. This must be strictly adhered to even by the most senior members of the Imperium. Even the high lords of Terra are unable to make inquiries into the Illuminate Pact's operations, without a formal written request presented to the Inquisition Ordo responsible for the overall overwatch of the various Pact members. But despite this, each of the Chapters do not boast of this stipulation or lord over this fact as the Pact is a closely guarded secret between them. Because of this, little to no one outside of the Illuminate Pact members know about this primary Tenant rule.
- Membership - Not particularly stated membership into the pact is quite simple -- all a petitioning group has to do to prove themselves is face the Ordo Hydra in battle. There is no restrictions on who can join the pact but given the secrecy of the Ordo Hydra, it is rare for representatives of the pact to invite the group in question to join.