Passive: Mutation
Mutation stacks are gained through Nidus’s abilities. Each stack in separated into five sections; gaining the fifth section will award one stack of Mutation, giving multiple benefits to Nidus
Virulence (#1) gives one section (1/5 of a stack) per enemy hit. Maggots spawned by Ravenous (#4) also give one section (1/5 of a stack) per enemy hit. Larva (#2) has a 50% chance of giving one section (1/5 of a stack) per enemy killed while affected by it.
Nidus can have a maximum of 100 Mutation stacks (increasable to 300 using his Augment Mod Abundant Mutation). Stacks do not decay over time and will not be lost during host migration. Nullifiers will slowly drain Mutation stacks, ramping up the longer Nidus stands in the affect.
Stacks of Mutation can be spent on casting Parasitic Link (#3) and Ravenous (#4). The number of stacks also increases the damage caused by Virulence (#1) and the maggots created by Ravenous (#4).
When Nidus takes otherwise fatal damage, fifteen stacks of mutation can be drained to negate the damage, heal for 50%, and give Nidus five seconds of immunity. If Nidus has less than fifteen stacks, this effect will not trigger.
#1 – Virulence
Virulence creates a long column of damage in front of Nidus. Every enemy hit generates one section (1/5 of a stack) of Mutation. Each enemy hit also refunds 25% of the energy spent to cast Virulence. The damage of this ability scales with Mutation stacks.
Usage
This ability has great synergy with Larva (#2). The easiest way to farm up Mutation stacks is to ball a large group of enemies and spam Virulence. You can do this forever as long as you have more than four enemies balled up in Larva because of the energy restored. At high levels of Mutation, this strategy can also produce a decent amount of damage as well.
Augment – Teeming Virulence
Teeming Virulence increases Primary Weapon crit chance as long as you hit four or more targets. This plays in well to the normal playstyle for Nidus, increasing the damage of your Punch Through Primary Weapon to the balled up enemies.
#2 – Larva
Larva is Nidus’s Helminth Ability
Larva shoots out a projectile that activates upon hitting a surface or enemy, or when you use the ability again. Once activated, Larva pulls in all nearby foes that are vulnerable to CC. The affected enemies are stacked on top of each other in a tight ball and are unable to act.
Usage
The most straightforward use for Larva is to stack up enemies to farm Mutation stacks with Virulence (#1). Remember though that if an enemy dies, you can no longer gain Mutation stacks from them. You can tell a Larva’d enemy is dead because their body will shoot out of the ball.
Larva is the perfect way to stack enemies for Punch Through style damage. Weapons like the Ignis Wraith or any weapon modded with Punch Through can easily hit multiple balled up targets. Melee weapons can also cleave through the group, quickly gaining combo counter and ramping damage.
Augment – Larva Burst
Larva Burst allows you to reactivate Larva once the enemies have been pulled in. This detonates the balled up enemies, causing increased damage for each enemy balled up.
#3 – Parasitic Link
Parasitic Link costs one stack of Mutation to create a link between Nidus and either an ally or an enemy. The link will break if Nidus moves too far away.
If linked to an ally, Nidus and the linked ally have increased Ability Strength.
If linked to an enemy, the enemy is stunned and Nidus redirects a percentage of the damage he takes to the enemy. The linked enemy has a large damage taken reduction, meaning it can take a large amount of redirected damage
Usage
Linking to an ally is one of the few ways to increase Ability Power beyond the normal maximums. If playing with an organized group, this ability can greatly increase the overall damage of the team. Nidus doesn’t benefit much from Ability Strength in high end content, so Nidus himself does not benefit much from the link.
Nidus already has a huge amount of survivability with inherent health regeneration, Mutation stacks triggering immunity, and because most builds can focus entirely on Armor without wasting mod slots on shields. Parasitic Link can further increase his survivability, making him one of the tankiest frames in the game.
Augment
None
#4 – Ravenous
Ravenous costs three stacks of Mutation to create a small area on the ground that heals allies and creates maggots that seek out nearby foes. The maggots detonate themselves upon reaching an enemy, adding a segment (1/5 of a stack) to Nidus’s Mutation.
Usage
Ravenous is a great ability to throw down if you are planning on staying in a specific area for a while. With a decent amount of enemies, Ravenous can quickly refund the spent Mutation stacks, especially if you ball up your foes near the maggots using Larva (#2).
The healing from Ravenous is great, but requires you to stand in the small area. If you are able to stay in the area, it is great. However, most Warframe gameplay has you moving about quite a lot, reducing the effectiveness of the ability.
Augment – Insatiable
Insatiable augments Ravenous to give Nidus a chance to gain an additional stack of Mutation whenever you gain a normal stack. You have to be standing inside the Ravenous field for it to work, so like the normal ability, this only works well if you are staying in one place.