This is a general use [Nidus] build for boosting critical chance (particularly on primary weapons), high range larva for grouping, high range link so you can be somewhat mobile and parasitic link for 90% DR which can easily tank base/early to mid levels steel path with ease (100-500), even without many mutation stacks. Virulence spam is used for stack gain, energy gain, crit chance boost and even low level DPS.

For endurance or level cap steel path (lvl 1000-9999) where tanking becomes useless and [Nidus] can simply stay immortal with his passive, you can remove Parasitic Vitality, Adaptation and Arcane Guardian for some combination of insatiable/larva augments e.g. here: https://overframe.gg/build/232438/

UPDATE APRIL 2024
The new augment [Parasitic Vitality] now replaces [Vitality], giving an equivalent amount of health after approximately 13 stacks of mutation. At rank 30, 100 stacks and 200 strength, you gain approximately +800% health giving 5850 health. If you slot [Abundant Mutation] for a meme only (since it is usually very hard to achieve 300 stacks outside of solo survival), you can hit +2400% health giving 16,250 health.

BUILD SPECIFICS

Duration
Lower duration is fine for larva since you can cast it sooner again in case you don't manage to kill all enemies, and 3 still has a reasonable uptime of 40+ seconds. Larva is better with slightly lower duration so it can be spammed more often, unless you are running [Larva Burst]. If you decide to run [Larva Burst], you can switch [Transient Fortitude] out for [Primed Continuity] to hit 150% duration.

Efficiency
Lowest efficiency is fine for [Nidus] since 1 and 2 only cost 62 and 39, 3 and 4 cost no energy and 1 even refunds energy, gaining tons energy when efficiency is low and you hit many enemies. Additionally, rage/hunter adrenaline allows for easy energy regen in case you miss virulence or somehow run out of energy and desperately need to cast larva/virulence. However, you can always maintain your energy with careful management of the 2 +1 combo, only casting virulence when there are at least 5 enemies within the larva (Each enemy refunds 15.5 energy, so hitting 5 enemies refunds 78 energy. You only need to hit 12 enemies to fill the total capacity of your energy pool from 0 energy without [Primed Flow]. If you run [Primed Flow], you need to hit approximately 33 enemies to refill the whole pool from zero).

Range
Range is essential for larva to pull as many enemies as possible from across the map. Range also helps maggot explosions and maximising the link distance on mobile missions. High range is slightly detrimental to virulence since you need to wait for it to end before casting again, but you can aim into walls if possible to shorten this and spam virulence. Once you hit max stacks, you only need to use virulence every 10s or so to refresh [Teeming Virulence] and any lost stacks.

Strength
Strength really only scales the damage of 1 and the crit chance boost of [Teeming Virulence]. For casual tanking, only 180% strength breakpoint is required to hit 90% damage reduction. Note the crit buff of Teeming Virulence applies additively to crit chance mods like point strike and critical delay/deceleration, and
and only applies to primary weapons.

Flexible Options

• Adaptation - good for lower levels like starchart and base steel path when you want to tank a bit more. [Adaptation] doesn't need to be max rank (could even be rank 0) with the only difference being the ramp up to 90% is slower , which makes no real difference to [Nidus] since he is inherently tanky, and the buff lasts shorter, which makes no real difference since stacks continuously get refreshed. Alternatively you can slot this in the overextended slot.
• Rage/Hunter adrenaline - can be useful if you have energy issues, but 1 can consistently return you to full energy and energy orbs spawn quickly enough. More useful in short missions where enemies are sparse.
• Steel Fiber - If you don't own Arcane Guardian, you can put this temporarily to boost armor

Augment slot (can run no augment):

• Teeming virulence - boosts crit chance of primary only. don't use this if you don't want to use your primary or your primary has incredibly low base crit chance. If you don't want to use [Teeming Virulence], you can reduce the overall power strength to simply exceed the 90%DR threshold of 180% (e.g. remove transient fortitude).
• Insatiable augment - faster stack gain while standing on ravenous (recommended for SP endurance for increasing stack gain)
• Larva Burst - lowish damage nuking and allows larva to be spammed rather than wait for duration to expire. You can add more duration if you use larva burst.
• Abundant Mutation - increases stacks to increase 1 damage and scale 3, but gives undying a cooldown. Fine to use on low level steel path or normal starchart where survival is not a big issue. Do NOT use this on endurance steel path since the damage of 1 scales poorly against armor without stripping and you become less 'undying'.

Stretch (- slot): If you don't care about such high range,

• Swap for Archon Intensify for even more power strength, which is activated by Ravenous

Exilus slot is completely flexible:

• Cunning Drift - for extra range
• Primed sure footed if you don't want to rely on link for knockdown resist
• Power drift - for extra strength
• Vigilante pursuit for addition radar

Aura slot is completely flexible and up to what you own:

Why no [Umbral Fiber]?
While alot of builds use triple umbral and [Nidus Prime] is a prime candidate for this, the benefit of adding it only provides 674 extra armor (resulting in total 80%DR), 22% extra power strength and 385 extra health. Furthermore, [Parasitic Vitality] is now far far ahead for giving HP and thus EHP and Arcane [Guardian] already provides 900 armor (resulting in 82.6%DR, and has constant uptime due to the lack of shields). 22% power strength is lower than that provided by [Archon Intensify] or [Augur Secrets], so you would be better off putting either of those. If you really want to commit to using Umbral Forma, you can, but it may mess up other build configurations that don't require any umbral mods.

Helminth
[Nidus] has a reasonably synergistic kit so is best run without helminth.
If you really want to subsume something, you will probably subsume into 4 or 3

Options that synergize well with high strength/ or high range (although you may need more duration to sustain):

• Nourish - gives viral dmg boost, viral status on damage and energy boost
• Gloom - CC and healing - replace stretch with Primed flow and consider swapping rage for primed continuity. Rely on Virulence to sustain energy for Gloom.
• Roar - universally good to boost virulence damage, weapon damage and ally damage
• Tharros Strike - full shield and armor strip a 200% str, very good into larva since it strips in a cone which hits the entire Larva easily
• Resonator - mass crowd control
• Elemental ward - more health or armor
• Breach Surge - minor crowd control and damaging sparks

You can even subsume ensnare over larva for an alternate style of play. Multiple ensnares can be cast at once, and while the mechanics are much slower/gradual compared to larva, and don't group them as tight, the crowd control offered by ensnare is slightly superior to larva due to it's spammability. Furthermore, you are able to headshot enemies easier and electric procs can even headshot easier compared to when enemies ragdoll in larva.

Here is a fun meme option using Reave to oneshot/nuke enemies within larva : https://overframe.gg/build/221813/nidus-prime/viral-reaver-nidus-one-shot-reave-steel-path/

Arcanes
Any arcane that triggers "on damaged" is ideal for nidus due to the inherent lack of shields:

• Arcane Guardian - provides basically the same amount of armor as Umbral Fiber pumping up damage reduction by 20%.
• Arcane Avenger - gives flat +45% crit change after all other bonuses, which pushes the crit chance even higher with teeming virulence
• Arcane Grace - passive healing for lazy immortality
• Arcane Agility - parkour fast!

Archon Shards2 Amber Cast Speed

3 Energy Max shards

PLAYSTYLE

1. Cast 2 to group enemies, making sure you catch at least 5 enemies at the minimum
2. Cast 1 into the ball of enemies to kill and build stacks, as well as generate energy
3. Once you have a single stack, cast 3 on a nearby enemy for 90% damage reduction and status immunity, or nearby ally for strength boost
4. Cast 4 when enough stacks for passive crowd control, healing and some AOE damage
5. Repeat 2 + 1 combo, until you hit max stacks
6. Recast 3 and 4 on expiry
7. Once at max stacks, cast 1 every 10-15s to refresh [Teeming Virulence] and and regain any lost stacks

WEAPONS

Obviously you can use anything you enjoy, but there are a few weapons that fit nidus thematically as well as synergizes with Nidus abilities.

• Bubonico : Infested arm-cannon shotgun with regenerating ammo that looks cool and feels cool. The secondary fire lobs three balls of innate viral damage with very high status chance. If you mod the weapon with electric and shoot alt-fire into a Larva ball full of enemies, all enemies will be 'primed' with viral status and electric status which will chain electric damage within the ball. Any enemies that don't die immediately can be finished off with the primary fire that has higher crit, higher damage, raw corrosive damage and slash procs from hunter munitions. Paired with teeming virulence and arcane avenger, Bubonico's primary fire crit chance hits approximately 180%.

  Anti-grineer build: https://overframe.gg/build/210444/bubonico/bubonico-grineer/
  Anti-corpus build: https://overframe.gg/build/217932/

• [Zymos]: Infested pistol that releases homing spores on headshots. Linking an enemy with parasitic link stuns them and makes them immune to knockdown and direct damage, meaning you can spam [Zymos] into a stationary target and let it release multiple homing spores to nuke nearby enemies.

  Insane crits and hemorrhage build: https://overframe.gg/build/218337/

• [Caustacyst] : Infested scythe with innate corrosive damage with a heavy attack gimmick that releases a relatively narrow wave of corrosive sludge which can stun enemies. Perfect for heavy spamming into a Larva ball. Furthermore, scythe heavy attacks have forced slash procs meaning it can actually kill heavily armored units in addition to a gimmick. Paired with arcane avenger and sacrificial mods [Caustacyst]'s relatively low base crit chance of 9% becomes a more reasonable 103.5% on heavy attack.

  Caustacyst Heavy Spam build: https://overframe.gg/build/218031/

• Dual Ichor (influence): https://overframe.gg/build/572811/

• Dual Ichor (slash): https://overframe.gg/build/580783/

Other cool infested primary weapons that can benefit from teeming virulence/avenger:

Other good infested secondary weapons include: