EU Military

The EU Military is the Europia United's collective military forces which are divided into individual national forces and referred to as "state armies," though the exact nature of these armed forces is not clear.

General Overview
From what is shown, the most used Knightmare Frame is the Panzer-Hummel, which appears to be somewhere between the technological level of the Chinese Gun-Ru and standard Britannian Knightmares, though they are shown to be quite effective against Sutherlands and Gloucesters at range. While the Chinese Gun-Ru is an inferior but mass-produced model used in swarm attacks, both the E.U. and Britannia have a quality-over-quantity approach to their mech designs: a relatively small number of elite and powerful (albeit more expensive) armored units are supposed to dominate the battlefield out of proportion to their numbers. The main difference between Britannian and E.U. design philosophy is that Britannian Knightmares have more close-range weapons meant specifically for hand-to-hand combat against other Knightmares. In contrast, the E.U.'s philosophy is that they don't have to fight Britannian Knightmares in close quarters combat if they can not get close enough to engage. Thus E.U. Panzer-Hummels don't have hands to wield close-range swords with, but instead their arms have integrated long-range guns. The E.U. forces have generally been able to hold their own on the battlefield against Britannia, and the strength of these different design philosophies really comes down to individual pilots and commanders.

These E.U. ground forces only make one significant appearance in the original series, in R2 Stage 03,Imprisoned in Campus. The E.U. pilots displayed enormous courage, attacking Suzaku with little hesitation in spite of his reputation as "Britannia's White Death."

The role of the E.U. ground forces is greatly expanded in Code Geass: Akito the Exiled OVA, as the main characters belong to the special ops unit W-0.

The EU state armies seems to be technological superior to the Britannian army, as evidenced by the common use of holographic systems.

Navy
The E.U. is described as having once enforced a blockade upon Britannia in cooperation with the Chinese Federation during the "Indochina Incident," which implies significant naval capability.

Air Force
Until now nothing has been shown about the State Armies air force, with the exception of one orange zeppelin used by the W-0 for high altitude recon. A space program is apparently also in use, as W-0 is deployed on its first  mission since Narva via a multi-stage rocket.

Infantry
EU infantry soldiers have been seen performing multiple roles from actual combat to desk work, their uniforms change from R2 to Akito The Exiled OVA, being grey in R2 and Blue in the OVA, this may be an indication  that the uniform is different in each state army. Their foot soldiers wear body armor that is similar to the types that their Britannian counterparts wear, however the helmet bears more resemblance to the German Stahlhelm (Whereas the Britannian helmet resembles a flattened version of the British Mk. 6 helmet) and they lack the rebreather devices that is common to Britannian troops. Their small arms bear close resemblance to the German G-36 and sidearms appear to be based on the Czech CZ-75 or Browning Hi-Power.

Knightmare Frames
The most used Knightmare Frame is the Panzer-Hummel, which appears to be somewhere between the technological level of the Chinese Gun-Ru and standard Britannian Knightmares, though they are shown to be quite effective against Sutherlands and Gloucesters at range, both the E.U. and Britannia have a quality-over-quantity approach to their mech designs: a relatively small number of elite and powerful (albeit more expensive) armored units are supposed to dominate the battlefield out of proportion to their numbers. Besides the Panzer-Hummel they also use the inferior Gardmare.

The W-0 also uses the Alexander series that are superior to the Britannian Knigtmares, however the High command ignores them as they were created to be used by the elevens who are deemed as sacrificial pawns, therefore the Alexanders and the Alexanders MkII don't possess cockpit ejection systems.

Vehicle
The EU use a large number of blue and green armored vehicles.

Special Forces
W-0 is a force composed  of Elevens that fight against Britannia in commando raids, however the EU High command uses them  as sacrificial pawns.

The Special Bureau is an elite force tasked with controlling the W-0 and protecting their main base.