1. Mass Effect 3 Achievements
  2. The One and Only achievement
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The One and Only achievement in Mass Effect 3

The One and Only

Defeat a group of Spectre-level opponents on Normal, Hardcore, or Insanity.

The One and Only0
2 guidesOffline Mode - These achievements require play in game modes that do not necessitate a connection to any online services.Single Player - These achievements can be obtained by a single player.Difficulty Specific - These achievements require that the game be played on a certain difficulty level.
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How to unlock the The One and Only achievement

  • SirLugashSirLugash
    05 Mar 2013 05 Mar 2013 05 Mar 2013
    141 1 26
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    In order to get this achievement you will first need to acquire one gold token to buy "Mirror Match" at the Armax Store.
    This is basically playing you against yourself (your Shepard that is) while the enemy Shepards use different classes.

    Now before I post the way I did it I guess that Tomjeh's way (as he pointed out in my "Simulated Hero" guide) will makes this quite easy.

    It's basically setting the combat difficulty in the options menu to "Narrative", beat waves 1 & 2 and let one enemy live in wave 3.
    Now switch the combat difficulty back to "Normal" and kill the last enemy, achievement should pop now.
    I didn't do it myself so I can't confirm whether or not this works.

    ---

    Now to the way I did it:
    - Map: Wingman
    - Enemy: Mirror Match
    - Score Modifier: Enhanced Damage Boost

    When the match starts, turn left and run to the far corner on the lowest level.
    Position yourself on the very last cover point and your squad mates on the two cover points before you.

    I used Garrus and Liara while I was playing Sentinel.
    Liara is very good for biotic combos while Garrus is good to get shields down.

    The most difficult part is that the enemies tend to rush your place, so you will need to make good use of powers like Overload or Biotic Explosions to stagger them.
    Also, it seemed to me like some powers can hit you even behind cover and stagger you, what makes you vulnerable for more biotic attacks which can basically drag you out of cover.
    If you keep your head in cover and watch your left and right to not get flanked, this should go quite well.
    Usually, the Infiltrator was the last enemy standing so keep an eye for your cloaked clone.

    I would also recommend using the M-7 Lancer as it has infinite ammo, so you won't need to run for ammo boxes.
    You're not going for points here therefore don't go for the bonus pickups in between waves as that can make your previous position an enemy spawn zone.

    That's about it, might take a few tries but I got it on my first try this way.

    Guide not helping? View 1 more guide for this achievement.

    Showing most recent comments. View all comments.
    DigitALxBulletsI can confirm that this method works as I've just unlocked it tonight smile next is the remastered edition when I get my hands on it smile
    Posted by DigitALxBullets on 22 Mar 21 at 00:05
    Jet KlaatuWhere is the combat arena? Sorry if it's a stupid question but the guide (and the others) don't tell you how to find the combat arena, I assume it's on the Citadel somewhere?
    Posted by Jet Klaatu on 25 Jan 22 at 07:57
    DigitALxBulletsIt's with the Citadel DLC, after you have access to your penthouse suite go out the front door to the promenade and strait ahead is the armex arena this is the place your looking for.
    Posted by DigitALxBullets on 25 Feb 22 at 00:10

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  • DigitalVanquishDigitalVanquish
    07 Feb 2021 08 Feb 2021 08 Feb 2021
    2 1 2
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    I completed this yesterday on Insanity, and it wasn't too hard: I did it on my first try.

    Class: Soldier
    Map: Wingman
    Squad: Javik; Grunt

    Shepard: M-7 Lancer V, with AR Piercing Mod IV and AR Magazine Upgrade V; Cerberus Nightmare Armour.

    Javik: Particle Rifle V, with AR Stability Damper V; AR Piercing Mod IV.

    Grunt: M-7 Lancer V, with AR Stability Damper V; AR Piercing Mod IV.

    Strategy: Play smart. I don't think I did anything particularly clever. Stick to cover as best as you can, and go from cover to cover when the grenades are thrown at you. Keep distance between you and the enemies, and use the terrain to your advantage for breaking their line-of-sight. As with the rest of Insanity in ME3, and so too on lower difficulties, make use of your squad powers - Grunt's Concussive Shot is very useful for setting off Fire Explosions, primed by Shepard's Incendiary Ammo, and Javik's Biotic abilities keep the enemies debuffed.

    I found the fight at the end of the DLC to be harder, for comparison. Grunt and Javik were particularly useful because they actually engaged the enemy, unlike some squadmates that just seem to stand around.

    I'm happy to try my best to answer any questions, if there's further details you feel you may need.
    Showing both comments.
    Jet KlaatuWhere is the combat arena? Sorry if it's a stupid question but the guide (and the others) don't tell you how to find the combat arena, I assume it's on the Citadel somewhere?
    Posted by Jet Klaatu on 25 Jan 22 at 07:59
    DigitalVanquishSorry, Jet Klaatu. I didn't see a notification.

    I imagine you've since found out where it is, but if not, it's part of the Citadel DLC - opposite the entrance to the apartment complex as you walk onto the Silversun Strip. It's Point of Interest 5 on the map.
    Posted by DigitalVanquish on 20 Aug 22 at 16:15
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