The Battle YMIR Mech, or Model 34-A, or more commonly called a Heavy Mech, is a massive killing machine designed for anti-infantry purposes. Clad in bone-white armor with red lights, they are utilized by Eclipse and Blue Suns mercenaries as infantry support. They are also used as security in some colonies and are frequently seen alongside LOKI Mechs.
Heavily armored and shielded, YMIR Mechs possess twin automatic mass accelerator cannons concealed in the right arm and a rocket launcher in the left. These arms will open when the mech is about to fire. The symbols and writings on their armor bear resemblance to the LOKI Mechs' and the robotic sounds made by YMIR Mechs during combat sound similar to geth noises; however, they occasionally "speak" in a low, robotic voice, referring to their status during combat. Like Geth Armatures and Colossi, they will "unpack" when deployed.
YMIR Mechs possess twin mass accelerator cannons in the right arm and a rocket launcher in the left arm. There is a noticeable audio delay before the left-arm rocket launcher opens fire. YMIR Mechs usually engage at point-blank range and will attempt to advance on enemies. The mech moves very slowly and loudly and cannot climb steps. It can fire its twin Cannons while moving, however it must pause to fire rockets.
The YMIR Mech will always explode upon their destruction. And as with LOKI Mechs, the YMIR Mech will explode when killed by a headshot; however, the "charge time", damage, as well as the visual effect of the explosion, are all almost identical to firing a shot from the M-920 Cain (see General Notes, below).
The YMIR Mech possesses high shielding and armour. They do not have any other defensive capabilities or defensive strategies as they tend to constantly advance on enemies to engage at point-blank range.
- YMIRs are very dangerous and tough enemies, and if encountered in combat, top priority must be placed on dispatching them quickly, as they will shred teammates and the player if caught in the open.
- This mech moves very slowly, allowing the player to perform hit and run attacks if the terrain allows it. It is possible to hide behind large containers and circle around them when the mech closes in.
- Try to fight upon higher ground. YMIR can only ascend ramps; if you can get to higher ground only accessible through climbing obstacles, you'll have an easier time destroying them.
- If you don't have a protected position, or if the YMIR is moving to flank you, retreat. Find better cover. Leave your squad mates to die if necessary. They will be resurrected when the battle is over. Better yet, you could wait for the mech to pass their bodies before reviving them, allowing them to start attacking the mech from behind while you keep its attention on you.
- Headshots are the most effective tool against the YMIR, and given their large heads it's fairly easy to consistently headshot them with most weapons at many ranges. The most opportune time for lining up headshots is the time the mech takes to switch between its machine gun and rocket launcher. The mech makes a distinctive sound when it loads or unloads its rocket launcher.
- Beware of the explosion caused when killing a YMIR. Getting caught in the blast radius when the mech 'overloads' after a headshot means a certain death, even when your health and shield are fully charged. There is a short delay before the headshot-kill and the detonation, with enough visual and audio cues to warn you of the impending explosion. Even when not killed by a headshot, the YMIR will still explode, albeit to a much less devastating degree. Still, the blast is sufficiently powerful to kill a critically injured character, friend or foe, and will dislodge anyone within the blast radius from cover for a few seconds.
- The YMIR's death-explosion damages everyone nearby. If you can lure it to a position where it is surrounded by many enemies, that explosion could save you a lot of ammo. If the YMIR mech is taken down by a headshot, the resulting explosion can be enough to take out or severely weaken (depending on difficulty level) other nearby YMIR mechs.
- More often than not, an YMIR will focus almost exclusively on Shepard, unless his/her squadmates are within targeting range and Shepard is not (the range at which the crosshair will bring up an enemy's name, health and protection layer info). If all other enemies are eliminated and the terrain allows it, you could play "ring-around-the-rosie" with the YMIR while your squad slowly whittles the mech down with gunfire and tech/biotics.
- Use Disruptor Ammo, Overload or Energy Drain to quickly nullify their shields. Duly note that the stun effect those powers usually have against mech does not apply to YMIR. Nor the weapon overheating effect.
- Use Warp, Reave, Incinerate, Incendiary Ammo, or Armor Piercing Ammo to destroy their armor. At higher ranks, Warp and Reave can briefly stun it when not attacking, though not to the point of cancelling its attack. Warp Ammo is somewhat less effective here, as it has lower bonus against armor, unless you can envelop the YMIR in a Singularity field.
- Pull, Throw, and Singularity can affect YMIR Mechs if their shields and armor have been destroyed however Shockwave will not knock it into the air (though it will still cause a stun if it hits the mechs shields). Stasis will paralyze YMIR normally and the YMIR is incapacitated for 3-4 seconds after the stasis wears off. Slam also technically works, but only lifts the mech a few feet into the air before "slamming" it back down fairly weakly, indicating its extra weight makes biotics difficult.
- Pull combined with Warp Ammo can quickly finish the mechs off when armor and shields have been dealt with. This is particularly effective with assault rifles and sub-machine guns.
- Combat Drones can be effective as well, since they distract the mech. If you target a YMIR, the drone will almost always materialize behind the mech. It will then slowly turn to destroy the drone, opening an opportunity for attack.
- If you have AI Hacking, you may use this to temporarily turn the mech into your ally. It is very powerful ally while it lasts.
- A fully-upgraded Charge, preferably Heavy Charge combined with the M-300 Claymore or M-22 Eviscerator shotguns are surprisingly effective against the YMIR once its armour is destroyed. This is because Heavy Charge not only provides a barrier that lasts for 100% of your total shields, but the time delay allows for 1-2 shots as well as additional time to escape the blast radius.
- Tactical Cloak can be used to easily reach new cover if the mech is close to your position but can also be used to take advantage of its low maneuverability. Position a teammate on the other side of the combat zone from you and cloak. At that point the mech will turn to attack your teammate. When your cloak drops, the mech will need to turn back around to attack you, which can give you several free seconds.
- Stasis can be a great way to gain a few extra seconds as it will take the mech out of the battle, which will allow your shields to recharge and allow you to reposition yourself. In addition, the mech will fall down briefly upon Stasis wearing off, giving you 3-4 seconds to shoot it when it's vulnerable.
- The M-622 Avalanche will completely strip a YMIR of its shields and armor, and freeze it (increasing its vulnerability to all damage) in three shots (normal difficulty), regardless of where the blasts hit.
- On Normal difficulty, the Collector Particle Beam will destroy a YMIR in roughly 10 seconds, if the beam is held on its head. On Insanity difficulty, it will take roughly 400 ammo of this weapon to destroy a YMIR when constantly aimed at its head.
- Heavy weapons such as the ML-77 Missile Launcher or M-100 Grenade Launcher will make short work of the YMIR. The Arc Projector is effective at taking out its shields. M-490 Blackstorm will pin the mech in place for a brief time, before the singularity field explodes.
- Sniper rifles and heavy pistols are good choice against YMIR, for their damage bonus against armor and their precision, making headshots easier to pull. The M-98 Widow is very powerful, and it only takes about 3 headshots from this weapon (when fully upgraded) to kill a YMIR.
- All of the weapons provided by the Firepower Pack are very effective against the YMIR. The Geth Plasma Shotgun can easily deal massive damage to its shields with an overcharge shot, and both the Mattock and Phalanx are very effective at ripping through its armor, with both guns being accurate enough to deal a killing headshot.
- The M-76 Revenant is extremely effective against YMIR Mechs. If loaded with Disruptor Ammo, one full clip is sufficient to destroy one on Casual difficulty, assuming all or most of the rounds hit it.
- YMIR Mechs are likely named after a frost giant from Norse mythology.
- Due to a YMIR Mech being present during Jacob's loyalty mission, it can be assumed that these units have been in production for at least ten years. This may have been a continuity error on the developer's part in light of other anachronistic technologies present in the mission.
- In Mass Effect: Infiltrator, Randall Ezno and a turian prisoner encounter similar mechs deployed by Cerberus, that appear to be modified or advanced versions of YMIR, equipped with technology salvaged from the Collector Base.
- The very first YMIR Mech of the game, the mech on Freedom's Progress on all difficulties with the exception of Insanity will not create the larger explosion if the mech dies from a headshot. It will simply explode as though you killed it with a shot to a body part other than the head, while on Insanity, the mech will still charge up its explosion upon a headshot kill.