Negative Warden - A Mag Build

Lately, I feel Mag is considered as more of a utility frame and her other prowess is rendered in shade. While it is far from universally-applicable, it's exceptional in areas where it is. The theoretical damage output scales just according to the enemies' durability and can reach stunning numbers while allowing for above average defense, even for one of the most fragile Warframes existant to date. And applied in practice, it allows for perseverance even in longer endless missions and other high-level engagements.

How Do I Mod?

Mod setup of the Warframe. Click to enlarge.

Overview: Potato in any case. The extra polarity Mag Prime has keeps you from needing a  Forma. If you have just Mag, get Mag Prime, it's among the cheapest of frames, you can even get it for 20 Platinum 20.

Strength and range above 200%. Duration is out of question. Efficiency useful, but not mandatory, just keep it positive.

Mod Rundown: Aura - Matching polarity. If you really want to spend a Forma on Mag, spend it here and change to to use Energy Siphon/Corrosive Projection depending on team needs.

Intensify + Transient Fortitude - Max.

Streamline + Fleeting Expertise - Max. Nerfed duration has no negative effect on build's play.

Blind Rage - Rank 6. No less. More isn't useless, but more on that later.

Overextended + Stretch - Stretch maxed. OE Rank 3. No more, no less.

Shield Transference - Highly beneficial augment for self-defence.

Defensive variant: Replace Intensify with Redirection, BR to Rank 9. Caution: High-rank Redirection may cause need of  Forma for slot.

How Does The Build Work?

Ability stats. Bullet Attractor excluded due to uselesness. Click to enlarge. Blast stat on Polarize is false. Drain over 100 has no further effect.

The centerpiece of this build and gameplay of it is Shield Polarize. It replenishes your shield, shields of your allies, cryopods, excatvators, consoles etc. and drains shields of enemies. Base is 50%, but the 200% Strength makes a single cast affect entire capacity. Then, another parameter multiplies the points drained and applies it in a damage explosion. Base is 2.5x and is affected by Strength. Damage dissipates with distance from explosion, Range affects the radius. Also, the explosion never harms the enemy where the shield drain occured, it only hurts other enemies nearby. This means one enemy doesn't kill itself. Two enemies can kill each other.

The augment of the ability makes half of the total shield drained with a cast applied to you as shield/overshield. Overshield is on top of your usual shield capacity and has a hard cap of 1,200 points. On high levels, it is possible to refill this cap with just two or three enemies around.

Damage scaling by Power Strength on a lv 80 Corpus Crewman. Click to enlarge.

Strength beyond 200% cannot give allies overshield, and does nothing extra with enemies' shields, but it can scale damage multiplier further still. However, the scaling of damage with one enemy drained is shallow beyond 200%, due to the fact you can drain 100% of capacity at most. Difference between 200% and 244% is just about 20%. While lowering efficiency for this may be deterring, also keep in mind doing this effectively boosts range.

Pull and Crush are well usable, and effective killing tools for up to mid-level thanks to buffed STR. Bullet Attractor always had little uses and the nerfed duration only furthers that.

How Do I Play With This Build?

Now, you may realize that since all of this build's power lies in using shields around her, never play this build against Grineer and Infested. It would be painful since you are rendered near-powerless against them.

You can fight against Corrupted, actually. Though it's true damage is weak against Alloy Armor, it can still make for quite a bang, clearing out a substantial share of incoming enemy waves. Also, if you see an Orokin Drone linking itself to a mob of enemies below it, it means even the "Grineer" units have shields that can be drained. In your eyes, Shield drones are nuke dispensers. Ultra-explosive barrels (applies to Corpus drones, too, more shields, more bang). But be careful since heavies, and a bit later, even Lancers, can survive the explosion and you will be left with conventional means of their disposal.

Do not spam Polarize. Casting twice in a row will cause no effect, unless more enemies walked in range meanwhile. All the shields will be gone, if someone survived, you will need to let them recharge or wait for another wave of enemies to appear. Depending on the mission, I cast every 10-20 seconds. If an ally or objective is getting hit, you can, of course, cast immediately to protect it, but don't spam it and start focusing on removing the source of damage.

In short, think of enemies' shields as fuel tanks and Polarize as a match to set them off, killing everyone.

Advanced Building

If you pondered over Mag's ability mechanics, you might have asked a question: "If I increased the Polarize explosion radius, I would boost the damage on an enemy that would be standing in a given distance from the explosion, right?" Your thinking makes sense, but I dug into it and found out it is not entirely straightforward.

We already know that base damage scales linearly beyond 200% strength. Damage actually dealt also scales linearly over distance from explosion and is zero at max range.

Linear function is ax + b. In our case, a as the tangent coeficient is b ÷ range and b is the base damage. That damage is calculated as Enemy Shield × 2.5 × STR[%÷100]. We will take a lv 80 Crewman as our model.

Scaling of damage over range with Rank 3 OE (green) and Rank 5 OE (red). BR Rank 8.

Whenever you change rank of Overextended, you increase range, but lower strength, or vice versa. This causes substantial lowering of the tangent coeficient, making damage fall off slower, on a shallow line. But it also lowers the absolute coefficient and therefore lowers the entire line graphically.

As you can see, in closer ranges, increasing radius is actually harmful to damage potential of the ability, an enemy has to be farther than 12.4m from the explosion for range boost to have a positive impact.

In addition, if multiple explosions occur near an enemy, only the strongest is applied. Under a pretense all enemies are the same, even if an explosion occurs that hits an enemy 20m away, there might be an explosion that is 10m away which would be applied instead and you would, in that case, deal less damage then if you had lower rank OE.

Therefore, in general, if you often strike at enemies that are grouped together, increasing range is not a good idea. If you have enemies stretched farther apart, increasing the range is a good idea.

Conclusion

I reckon there might be comments in spirit of you having used this before or being well familiar. But in most of the Corpus/Void mission I've ran, I was the only one having such built Mag, if I even equipped it myself as I was needed as a Nekros at other times.

Otherwise, I hope I managed to enlighten you on yet another of more creative ways to utilize Warframes that do require some effort to play, but compensate for it with a more variant, engaging gaming experience, on contrary to press-4-to-win. If you liked the guide, feel free to direct lost souls here and enrich the comment section with your praise, or questions! Thanks for reading.