Codex

Codices appear to be digitalised security systems utilised during the Ethereal occupation of Earth. After the Human resistance formed from the remnants of XCOM acquire access to the ADVENT coalition's data network for intelligence, Codices are physically deployed in combat against the resistance fighters.

Description
The Codex is considered a mechanical being when deployed in combat. the head, resembling a robotic brain adorned with a pair of eye-like sensors, metallic spinal chord and a black smoke-like substance flowing from behind like hair, is the only physical part of the body. The rest of the body appears to be a semi-solid hologram similar in shape to a female humanoid body. Codices have also been stated to fluctuate between dimensions, causing them to appear as though they are constantly vanishing and reappearing where they stand.

Abilities
In combat, Codices are typically armed with standard beam rifles and are capable of teleportation to evade danger or flank enemies. They are also capable opening psionic rifts which disable weaponry caught within and, after a short time, detonate causing devastating damage to anything within.

In the event that a Codex is non-fatally wounded, it can create a duplicate of itself independent from the original at the cost of half of its remaining vitality, which is transferred to the new copy. Whether this is voluntary or a pre-programmed reflex in response to damage is unknown.

As demonstrated by a Codex captured and interrogated by XCOM, they may wirelessly download information from external computer systems and even self destruct if they are used against their masters.