The Aura Forma is something I never really expected to see in Warframe, but really, after the addition of the Umbral Forma, I shouldn’t be that surprised. I mean, with one new type of Forma, there were guaranteed to be more in the future. Still, the Aura Forma is quite a weird place to start.
Aura Formas can currently be obtained in two ways: either as rewards for rare events or as a rare reward in Arbitrations. The Arbitrations version drops as a blueprint that you then have to build, and is actually more expensive than building an Exilus Adapter from scratch, costing a grand total of 4 normal Forma and a ton of Nitain, which is awkwardly hard to get right now. The Aura Forma as a complete event reward tends to be the last reward for the hardest mission, as it was with the Hostile Mergers Operation that recently finished.
What the Aura Forma does is quite simple. You stick it in a Warframe in the Aura slot and you can now use any Aura you want, no matter the polarity, and without any downsides. That means you can freely switch between polarities and still keep your +14 mod capacity, whether you use an Aura with a V, D or other polarity.
This does sound quite useful in theory, but when it comes to actual usage, there aren’t many times where you will be using anything other than an Aura mod with a – polarity.
The best Aura in the game is by far Corrosive Projection, which reduces enemy armour by a good percentage. A few of the other useful Aura mods use the same polarity – Energy Siphon (regenerating energy) and Shield Disruption (the shields version of Corrosive Projection) most notably. Corrosive Projection though is so strong that you can use it on literally any frame and it’s more effective than any of the other Auras, even the weapon-specific buffs. That means that there’s very little reason to really swap to a different Aura. If you’re not using Corrosive Projection, you’ll be using something specific to a Warframe (for example Sprint Boost on a Speed Volt), and either not have to change the polarity or won’t ever need to change your Aura.
In fact, there’s only a handful of frames where you might want to change your Aura on a regular basis. The most notable case is Nova, who has several distinct builds – one where she slows everything down and one where she speeds everything up. To do the latter, you would most likely want to use Power Donation, which has a V polarity, to further reduce your power strength, while you’ll probably want Corrosive Projection on the former build to make enemies easier to kill while they’re slowed.
Chroma could also make use of an Aura Forma, since you might want to use a weapon-buffing aura rather than Corrosive Projection. Or they want to be able to use Steel Charge for the extra mod capacity.
But that kinda means investing in Chroma and Nova, two frames that I just don’t like playing. If anything, I’m only ever going to use an Aura Forma so I can swap between Steel Charge and Corrosive Projection. Which probably means that I’ll be putting the Aura Forma on Volt Prime, since I use him the most. But I’m going to wait for a bit because I’ve got a bunch of pain in the ass weapons to level up, and I don’t want to be leveling up weak weapons with a low level Warframe.
On the plus side, at least you’re not restricted to one Aura Forma ever, so I don’t feel like I’ll be wasting this one…