Auxiliaries are special units that can be used to bolster your armies. Generally, all auxiliaries cost wealth, although for some units a secondary resource is required. Infantry auxiliaries are available in the Colonial, Imperial and Machine Eras, while the cavalry auxiliaries make their appearance during the Mercantile and Industrial Eras - as do the powerful "national guard units".
Generally put, auxiliaries are all based at two different buildings. Most foot mercenaries are based at your Sanctuary building, while cavalry can be recruited from the Fortress. At any given time, the number of mercenaries available to you from your the Sanctuary is three, while cavalry mercenaries, usually two in number, can rise to four with sufficient research. Mercenaries are usually weak, but with proper research, they can be exceedingly strong.
There are special auxiliaries in  and  which are dependent on what sort of government you research. These are extremely powerful units. Generally, red governments have access to very powerful cavalry units, while green governments can expect their auxiliary infantry units to be upgraded to a Republican Guard line in  and  once they research the correct Attrition technologies at a tower. Republican guards are powerful units, but like the  cavalry opted out to select them, they are highly expensive.
Although some mercenaries can be very, very powerful and indeed a lifesaver at the start of the game, you must keep your happiness rating up. If it falls to 0 or lower, mercenaries will immediately desert your for any faction with the highest score, so long as they are not any one of the green-only mercenaries.
Colonial Era AuxiliariesEdit
Cavalry (slot 1)Edit
- merchant cavalryman (c) (all except as shown below)
- Tuareg archer (c) (Turkey; Bedouin)
- Qizilbash (c) (Iran, India)
- Greek stradiot (c) (Spain, England, Italy, France, Sweden; Netherlands; Austria)
The following can be upgraded by European or American factions to the Republican Guard, or into the All-Victorious Army upon researching Mercantile Governance and Liberalism. While these units share the same stats as a musketeer, they have no minimum range, and an attack, range and rate of fire similar to a grenadier guard). These units in later ages can be upgraded to the Presidential Guard along with other mercenaries of that period.
- Ghuzat Volunteers (India; Turkey; Malaya; China; Bedouin; Iran) fast-training light melee
- Ronin (Korea; Siam; Myanmar, Japan) weaker version of a Japanese samurai
- Tribal Archers (Sweden, Russia)
- Swiss Guards (Italy; England; Netherlands; France, Germany; Austria - these units don't upgrade to Republican Guard, they become Line Infantry)
- Native Archers (USA, Spain, Aztec, Portugal) Has stealth ability
- Native Spearmen (Mexico, Inca) Has stealth ability
Mercantile Era auxiliaries (slot 2)Edit
- Shaturnal (China; India)
- Stuart Exile (Netherlands; Malaya; France; Spain, Portugal, India)
- Hessian cavalry (England; Austria; Sweden; Germany; Italy, Russia)
- Mercenary mahout (China, Iran)
- Native horse (Mexico; Peru; USA; Siam; Bamar; Vietnam)
- Saharan jihadis (Bedouin, Turkey)
Green: (see  infantry auxiliaries)
Imperial Era auxiliariesEdit
Cavalry (slot 3)Edit
- Afghan light horse (c) (India; China; Iran)
- Bajau mercenary (c) (Japan; Korea; Siam)
- Gajnal mercenary (c) (Malaya; Myanmar)
- Jazda (c) (Peru; Italy; France, Germany; Sweden; Austria; Portugal, Netherlands) (c) - this is a lance-bearing version of the HGG.
- Circassian cavalry (c) (Turkey; Bedouin)
- German Legion (Russia, Britain)
- Native Scouts (c) (Mexico; Spain; USA)
The following can be upgraded to Regimental Zouaves. Zouaves are light infantry units, capable of taking on the light skirmisher line abandoned after the Imperial Era...but are extremely fragile, despite being crack shots.
- Irish Brigade (France; India; Mexico; Peru; Spain) - based off the Russian petrine musketeer.
- Armatoloi (Russia; Turkey) - based off an Ottoman azap
- Foreign Chasseurs (Austria; Italians; Sweden; USA; Germany; Iran; Japan; Korea) - possibly based off the German pandur
- Mercenary Sepoys (Myanmar; Siam; Portugal; Britain) - based off Indian infantry
- Hokkien rabble (Korea; China; Malaya; Myanmar)
- Black Watch (UK only, upgrade of Garde Écossaise)
- Black Guards (Bedouin)
For the UK, the Black Watch is available upon completion of research of Absolutism
Industrial era auxiliariesEdit
Red (slot 4):
- Repeating horse rifle (USA; Mexico)
- Booi (Japan; Russia; Korea; China)
- Terek Cossack (Turkey; Germany; Iran; India)
- Confederados (Portugal; Peru; Maya)
- Mercenary sowar (England; Netherlands; Myanmar; Malaya; Siam)
- Algerian Turcos (France; Spain; Bedouin)
- Uhlans (Austria; Germany)
Green: (see  infantry auxiliaries)
Machine era auxiliariesEdit
- Chasseurs d'Afrique (Portugal; France; Turkey; Italy; Bedouin)
- Gurkha rifles (Myanmar; Britain; India; Malaya; Thailand)
- Colonial Grenadiers (Netherlands; Japan; USA; Spain; Myanmar)
- Mongol Tribsmen (c) (China; Russia; Korea)
- Gauchos (c) (Peru; Colombia; Mexico)
- Gordon's Highlanders (UK only, upgrade of Black Watch)
The Gordon's Highlander Regiment is available only if you have researched Royal Prerogatives at your Senate.