Epidemic: A Crit-based, Strain-using, Helminth-equipped [Nidus]
This is an endgame build because it, with the 3 weapons and the [Helminth Charger] all need a stupid amount of forma.
The good news is that [Nidus] is (as always) a solid Endgame frame. Adding in the helminth+strain set means you get a little %Health damage, lots of weird crit potential, tons of self (and team) sustain, DR if you need it, direct player boosting (if you both need it), and a bunch of little bits and bobs.
The bad news is again, it's expensive as hell. The build is extremely tight, even with an umbral forma. A lot of folks don't care for the Synapse, nor want to farm/trade for the [Nukor]. [Hirudo] is kinda silly. And of course, there's better weapons, better companions, and better mods.
Thankfully, the synergy between all this means your pet never dies, you never die, and everything just eats it quick while you run around with 95+ stacks of mutation and can pretty well much face tank anything and everything. Neat!
I aimed to get as close to maxDR and Max Str through parasitic leech as possible, while having some solid health and armor numbers. Umbral is almost a no-brainer here. You can definitely swap all three out for Gladiator Mods, more Range, or similar, but when it comes to Arbitrations and nastily scaling folks, you'll want a chance to take maybe a hit or two. [Adaptation] could fit as well, but I found I had energy issues if [Hunter Adrenaline] couldn't get a couple solid whacks in. YMMV.
I like the occasional knockdown miss, which is probably the #1 shortcoming of this build. But, the things capable of knocking you down are also likely going to be caught up in your constant larva spams, so it's debatable. Mostly this is here to get us inches away from a full 200%, for the bonus to parasitic link, mostly.
For most situations, i would prefer my Larva to have a bit more Range rather than Duration. IIf you want duration, fine, swap this out for a [Primed Continuity] and such. Larva is an intensely powerful CC, probably the best in the game, so unless you want to drop this build and include Larva Burst, you will find situations where a too-long Larva ends up in a death of some sort just because you can't recast it in time to gather everyone up.
Energy economy. Yes, sometimes certain missions with dozens of parasites can bring you down a bit, but that's what larva is for. Flow isn't necessary, and I doubt I'd ever need an equilibrium or a streamline/fleeting. You have no shield, so just take the (little) hit, keep spamming out carpets, and parasitically link anyone you need. You'll be fine.
This could almost be left off your build, but it's nice to get the full bonus for Strain. Since this is a themed Endgame build, it stays. Keep in mind that with the rest of your build, the healing is almost pointless. Even with [Umbral Vitality] and [Physique], it's 4% of your missing health that's returned. Yes, if you somehow gobble up 25 maggots, that's 100% of your missing health, but... then the calcs are different and you're still barely getting a health orb's worth of healing when... yeah. It's not the greatest. But GIANT PLAGUE DOGGO is, so we keep it. I guess I could think of a scenario where it's like "Okay if you have fifty dudes shooting at you and you can't dodge or larva in time, and you have 4k health, and are down to 1 health, that means every maggot gives you 150 health" but yeah, that's 150 health... whoop de doo!
Also, as far as I can tell, the maggots from Strain are of a unique species unrelated to [Nidus]' maggots, the [Pathocyst] maggots, and whoever Hek is yelling at on the Plains of Eidolon. Which means that no, unfortunately you can't super overload on dead-maggot-dining, which to me is a terrible broken game mechanic and should be fixed. Until then, that means we just top up our health with [Hirudo] and call it a day.
Plop down your Ravenous Infestation, sit in it. Grab everyone into it. Slam away with carpets. Get 40% more stacks. Laugh as everything gets hit by your fifty different species of maggots, and... yeah. Lotsa stacks. You want all the stacks. All of em. So get to it.
With all this spamming of your handy Larva Spam, Virulence Spam, all backed up by the second carpet from your Parasitic Link spam... Why not get some crazy Primary damage while you're at it? With the recommended [Synapse] build equipped, your 97.5% crit chance (with maxed [Point Strike]) suddenly hits ~190%. A buff from a teammate and suddenly you are seeing redcrits everywhere. But if you don't like this, you can swap it with another augment, I won't cry. I just like building in more Crits to be on-theme.
Aura mod. Throw on an Aura Forma, and basically put whatever you want here. I like [Physique] because I like having a healthy bar, but it can just as easily be [Growing Power] or [Steel Charge] or whatever you like the most.
- Arcane Avenger and Strike
You will get hit all the time. So much hit. Avenger means if you get hit, you'll prolly get crit chance. What they don't tell you is that the CrCh you get is added after everything else on your weapons, as a flat buff. So if your weapon tops out at 90% Crit Chance, this triggering would take you up to 135%. That's nuts!
Strike is there mostly because I don't have a lot of Attack Speed on my [Hirudo]. Maybe one day after I get a decent Riven roll, but yeah. This can be flex, but I like strike for now.
On theme with the look and the crits. I recommend punch through for stacking viral/etc on folks stuck in your Larvaball. can easily orange-crit everything to death and back.
Same idea.... lay on status/crits while everyone is in your larva ball. Or slap em with Virulence again. [Kuva Nukor] chains similarly to [Atomos], but has a massivley high Crit Damage multiplier.
Yeah, [Hirudo]! It has a naturally high crit, which it can heal you off of, and combined with the strain set means you see crazy dumb damage numbers early and often. Even after the Blood Rush/Status/Enemy-EHP-Changes, you can wreck faces. It's also why we have Arcane Strike up there...
Yay, Plague Doggo! Mostly here because strain is hilarious, and every boy needs a dog. Helminth will be happy and healthy for a long time while linked via armor+health to [Nidus], which is nice. Plus he gets big. And there are maggots. Lots of maggots.
And that's that. Search for LJ's Epidemic to see what other parts of the build to work on if you have forma to burn.