Armageddon has a massive population and is capable of raising a large number of Imperial Guard regiments in times of war. At the height of the second Armageddon campaign, dozens of regiments were fielded from troops raised from Armageddon alone. Armageddon Imperial Guard regiments are made up of a mix of infantry, artillery, armour and Mechanised Infantry Companies. However, the highly industrialised nature of Armageddon means that a far higher proportion than normal are Mechanised Infantry, and it's not uncommon for over 90% of a regiment to be made up of such units. It is for this reason that regiments raised on Armageddon are known as Armageddon Steel Legions.
For the official Q&A covering this and the rest of Codex: Armageddon's army variants, see Codex: Armageddon Q&A.
Armageddon Imperial Guard Companies
As noted above, infantry, artillery, armour and, most famously, Steel Legion Companies are raised on Armageddon. In addition, some regiments have had years of experience fighting against the Orks that inhabit the jungles of Armageddon Prime, and therefore qualify as Deathworld Veterans. This plethora of different types of unit means that the following types of Companies from Armageddon can be used in games of Warhammer 40,000. In addition, each type of army can either be a 'tithed' army or a 'planetary defence army', which affects the types of unit it may use, as described below.
| Unit | List Used |
|---|---|
| Infantry Companies | Codex: Imperial Guard (Deathworld Veterans units may be included using the rules in Codex: Catachan) |
| Steel Legion Mechanised Infantry | Codex: Armageddon; Steel Legion Mechanised Infantry list |
| Armageddon Prime Jungle Veterans | Codex: Catachan; Deathworld Veterans list |
| Armageddon Sentinels | Sentinels in any Armageddon force can be armed with either a heavy flamer +5 pts; multi-laser +10 pts; lascannon +20 pts. |
Tithed and Planetary Defence Regiments
Armageddon is often called upon to raise regiments for major battles and campaigns all over the Armageddon sector. Regiments that fight off-world like this are called 'tithed regiments', after the process used by the Departmento Munitorum to call them up. Tithed regiments are supplemented by troops raised on other planets which are not found on Armageddon, such as Rattlings or Ogryn, as well as certain types of vehicle that are not manufactured on the planet. Tithed regiments are well-represented by the existing army lists, and so the army lists can be used 'straight', without any modifications other than those noted above for the Steel Legion Mechanised Infantry Companies. As an aside, it's worth noting that a number of tithed regiments stationed on planets close to Armageddon were recalled to the planet both in the Second and Third Armageddon campaigns, so you can use 'tithed' armies for games set on Armageddon itself if you wish.
Planetary Defence regiments are those that are raised to fight exclusively on Armageddon. They are different to tithed regiments in that there are certain units that they may not use, while there are a number of unique auxiliary units that they can use and tithed regiments cannot.