I thought that there could be a mod that adds a new enemy faction: a human terrorist organization known as the Aeon Alliance, rivals of XCOM. They in some ways resemble EXALT in XCOM Enemy Within, as they have sought cooperation with the aliens while steering clear of them while undermining XCOM. However, the Aeon are generally more violent and are of a more brutal agenda than EXALT as they sometimes would decide to launch an attack on a major city, lashing out at innocent civilians there and if enough Aeon Craft was shot down, assault an XCOM base. They claim themselves to be cast out from humanity and see the aliens as their salvation and the rest of the human race their enemy. Of course, Aeons share a similar behavior to aliens. At the beginning of the game, after you place your first base, the Aeon place their first base in a country not containing an XCOM Base.
Aeon soldiers are similar to XCOM soldiers, and share hair and skin color for both male and female. However, Aeon soldiers are dressed in Red sleeveless shirts and black pants and shoes for no armor; and black boots and gloves, red pants and shirt with black armor pads for equivalence of personal armor. For power suits and flying suits, Aeon soldiers wear red colored power suits with a black helmet of different shape.
Aeon soldiers are statistically similar to XCOM soldiers, and mid-game deploy psionic soldiers. The Aeon uses generally the same weapons XCOM uses, conventional weapons early on, laser weapons after some time, then plasma weapons late game. They also use various grenades and explosives and medkits. Aeon soldiers generally are affected by fatal wounds the same way XCOM soldiers are. Overall, Aeon troops are generally trained to the standards of XCOM soldiers and their primary weakness among the alien enemies is their bravery; after all they are human.
Aeon Bases are generally composed of the same modules as XCOM bases, randomly generated during XCOM raid on them. For that, attacking an Aeon base resembles XCOM base defense, but with XCOM soldiers being the attack and the Aeon soldiers the defender.
Aeon craft from weakest to strongest:
Fighter
Gunship
Transport
Heavy Fighter
Advanced Gunship
Assault Transport
Aeon missions include:
Hacking (craft lands near XCOM base to slow down research while landed)
Propoganda (spread propoganda in a country to pressure it to reduce funding)
Diplomacy (attempt to convince a sponsor to sign a pact with the aliens and withdraw from the project)
Harrassment (launch a terror attack on a major city)
Expansion (set up a new Aeon Base)
Assault (attack an XCOM base)
If the Aeon's last base is taken out, the Aeon will be officially wiped out and will no longer be able to conduct operations for the rest of the game.