A Codex of Enemies and Tactics

This guide will focus on the aspects of many enemies in the game and tactics to use to defeat them. Mass Effect is all about teamwork to strip enemy defenses, so this guide should help you coordinate.

Spanish and Russian dubs translated by Google Translate should be released soon.

The Basics

Please note; this guide is a WORK IN PROGRESS. I will add more info when I feel like it and when I find it. Please feel free to comment about anything you would like to see, or if you just like/hate it that's perfectly fine too!

So you've clicked on this guide and am now in here. Congrats! You are now seeing a codex.

Before we dive in I should alert you that these analyses have been taken on Hardcore difficulty. Also, amount of HP will be referring to other bars (for instance, Hardcore and Casual will have the same amount since it's still the same ratio to other bars). All contributions are welcome if you have info from higher difficulties or tactics. Thank you.

The basic format will be here:
[Enemy Name]
Type: [Organic or Synthetic]
Health: [Bar Type <toughness> etc (Bars in Parentheses mean that they will only appear on Hardcore or Insanity)]
Tactics: [What it usually does]
Powers:

Weapon Type: [how it shoots]Attributes: [passive abilities]Priority: [how much you should probably shoot it]Strengths: [abnormal resistance to certain things (excludes health bar resistances)]Weaknesses: [abnormal weakness to certain things (excludes health bar weaknesses)]Alignment: [enemies it sides with and are most likely to be found with][Description of enemy]Tactics[stuff to do when encountered]Tips[useful stuff to know]

Robots

Ahh, robots. The cannon fodder of cannon fodder.

Robots can be pretty easy to deal with if you take them out quickly, otherwise they can become a serious threat. Robots are usually resistant to afterburn and weak against electric damage due to their synthetic nature.

Not to be confused with Geth. Geth are a sentient species. These robots simply function to do whatever they're supposed to do.

Hacked/LOKI Mech

Hacked/LOKI Mech
Type: Synthetic
Health: Default [Medium] (Armor [Medium-Low])
Tactics: Close in and concentrate fire
Powers: None
Weapon Type: Heavy Pistol
Attributes: Brittle Volatility (Explodes if killed by melee), Unstoppable (More difficult to be CC'd), Fragile (Can lose limbs)
Priority: Medium
Strengths: Afterburn damage,
Weaknesses: Electricity
Alignment: Robots, varies

LOKI Mechs are called Hacked Mechs when you first encounter them in the prologue mission where Shepard wakes up and proceeds to evacuate the Cerberus facility. This is due to the fact that they were supposedly hacked by Wilson. They're usually found in groups of two to three and can be devastating if left alone to close in on you. Shoot them at every opportunity if you don't have more important targets.

Tactics:

On Hardcore/Insanity, LOKI mechs will have Armor. It's still generally advisable to use electrical skills and hazards. If they're not available, switch to your AR/HP to eliminate the armor. The rest should be easy to do.

Otherwise, use Overload or shoot them.

Tips:

Shooting the limbs of a LOKI Mech can blast them off and reduce its capability. If both arms are removed it may run at you in a suicide attempt. Kill it quickly.

You may find crippled mechs in some missions which are unable to fight back and can die in one hit. These are purely for cosmetic effect.

FENRIS Mechs

FENRIS Mech
Type: Synthetic
Health: Default [High] (Armor [Medium])
Tactics: Flank and expose
Powers: Stunning Strike (Attacks the player which forces them out of cover and into hitstun)
Weapon Type: Melee
Attributes: Volatile (Explodes on death), Unstoppable (Harder to knock into hitstun)
Priority: High
Strengths: Rapid-Fire, Melee, burning
Weaknesses: Electricity
Alignment: Robots/varies

FENRIS mechs are a PITA to deal with and can be big trouble if not dealt with quickly. Their strikes can force a player out of cover which can mean instant death on higher difficulties. They are usually found with enemies that can attack from a ranged distance.

Tactics:

Shoot the ♥♥♥♥ out of those ♥♥♥♥♥♥♥♥♥♥♥♥♥. Oh god please.
Oh also they have armor so burn that too

Tips

Shoot it.

YMIR Mech

YMIR Mech
Type: Synthetic
Health: Default [High], Armor [High], Shields [High]
Tactics: Mobile artillery turret
Powers: None
Weapon Type: Machine Guns, Rocket Launcher
Attributes: Nuclear (Explodes in a BIG explosion when killed, with a long delay), Literally Unstoppable (Cannot be hitstunned)
Priority: Medium-High
Strengths: Rapid-fire weapons and burning
Weaknesses: Electricity
Alignment: Robots/varies

Believe it or not, YMIR mechs are not the biggest concern in the battlefield. Sure they can be annoying and give you less opportunities to shoot, but they have a simply attack pattern. They fire their machine guns, stand still, fire a rocket, an then move again while venting heat, giving a short delay to attack before they start up again.

Tactics:

Take your sniper and aim for the face. Then just keep shooting.
If you do NOT have a sniper (because you actually play a unique class unlike soldier main me, cheers for you!) then use whatever abilities you have at your disposal to whittle it down. Be careful if you DO snipe it, as the rocket can cause hitstun.

Tips:

When the YMIR's shield and armor layers are gone, he becomes vulnerable to certain movement manipulation abilities such as Pull. Use this to gain a window to rain hell on it.

Assault/Rocket Turrets

Assault/Rocket Drone
Type: Synthetic
Health: Shields [Medium-Low]
Tactics: Settle and fire
Powers: Relocate (Fly up from spot and move to another spot)
Weapon Type: Machine gun/Rocket
Attributes: Volatile (Explodes when killed)
Priority: Medium
Strengths: Anything that doesn't do well against shields
Weaknesses: Anything that does so well against shields
Alignment: Robots

These guys don't make many appearances other than the mission that occurs after the prologue. It almost feels like these guys were almost finished developing, but then they said "♥♥♥♥ it" and scrapped them for the rest of the game. It's kind of sad, really. They're a new and unique enemy.

Tactics:

If it hurts shields, use it.

Tips:

See tactics.