This guide also takes into account if your team is using “Corrosive Projection” Aura on 4 players or not. Corrosive Projection (aka: CP) at max level reduces enemy armor by 30% and each player using this stacks with each other. A full team of players using Corrosive Projection lowers enemy armor completely! This is why you always want to run your high wave groups with people who all use this aura. (Note: Raids which can have up to 8 players only need 4 players using CP)

Therefore, damage combos vary depending on whether or not your team will be using this aura. In groups where no one uses the aura, you need to reduce armor on certain types of enemies with your corrosive damage type (ex. high level Grineer, Infested & Corrupted).

In groups where 4 people use CP aura, you can focus specifically on damaging the vitality of mobs, since using corrosive to reduce armor is no longer even needed. At this point, you will completely replace corrosive with viral when using it against Grineer and Corrupted mobs.

The reason Viral takes precedence over other vitality damaging types; is due to the fact it is a percentage based damage dealer. It scales no matter what level the target is. Also, by freeing up the toxin mod required to create corrosive (electricity + toxin), you can now form Viral combo (cold + toxin). It should be noted that Corrosive is more useful over Viral if you “have to” reduce armor to mitigate damage reduction. However, if your team uses CP there is no need.

Keep in mind, Viral is not an ideal vitality damaging type for every mob in game, even if you’re using team wide CP. Example, infested has a strong resistance against Viral. Also, in cases of Tenno and Corpus pure Toxin is better since it can directly bypass shields (Viral is still very useful on their vitality, but since they have shields it nice to instantly bypass the shield).

Please refer to the lists below to see when to use it.