One of the most annoying enemies in the game. They don't pose a serious threat, but are extremely hard to eliminate, especially during the first weeks of the campaign, where your soldiers lack any real firepower. The enemy's ranged attack does low damage, but similarly to Sectoid, the Codex's powers lie in her abilities. Those are:
- Teleport. The Codex can teleport almost anywhere on the battlefield, without causing overwatch and reaction shots. Thanks to that, the enemy can appear literally anywhere and easily flank your soldiers.
- Clone. Whenever the Codex receives damage from any source, she will clone herself, dividing any remaining health between the two copies. The clone is almost identical to the original, deals the same damage and the only difference is that it cannot use the teleport ability and dealing damage to it won't cause it to clone. When the original is slain, one of the clones gains the ability to teleport and clone.
- Psionic Rift. One of the worst abilities that your soldiers can be hit by. Everyone in the area has their weapon turned off, emptying the clip of the bullets, forcing your soldiers to reload if they want to shoot. Additionally, after a round, the bubble collapses, dealing psi damage to everyone in the area of effect. Secondary weapons, such as pistols, are unaffected by the skill.
To limit the amount of clones running around the battlefield, you should eliminate the enemy with a single strike. The Ranger soldier with the Rapid Fire ability is best suited for the job - two attacks from point-blank range are guaranteed to take out the Codex before she can clone. Remember to not use the Skulljack on this enemy - doing so will summon a powerful enemy, Avatar, who will make a short work of your team if they are not prepared for the encounter.