Event: Operation Plague Star

Operation: Plague Star is a recurring event involving the Infested on the Plains of Eidolon. As this is the first time it's returned since I started this blog, I thought it worth some time doing a write-up of it.

To participate in Plague Star, go to Cetus and talk to Konzu. While Plague Star is active, he will have a special Bounty assigned for it.

Stage 1: Retrieve Toxin

The first stage involves venturing into a random marked cave and retrieving a canister of Thrax Toxin. Grab the canister and get out of the cave.

Stage 2: Prepare Toxin

Once Konzu and Vay Hek finally finish talking, you will be directed to take the canister to a (usually) nearby marked Vault.

Open the Vault and insert the canister into the mixer to begin a 3 minute (Im)mobile Defence.

While the Toxin is mixing, you can add in Infested Catalyst and Eidolon Phylaxis. The Infested Catalyst blueprint is researched at a Dojo's Bio Lab, while the Eidolon Phylaxis blueprint is an event reward. They must be added to your Gear Wheel before starting the mission, and up to 4 of each can be added.

Once the Toxin is mixed, retrieve the canister from the console.

Stage 3: Deliver Toxin

You will be directed to take the Toxin canister to a nearby marked Drone, which will deliver the Toxin.

Escort the Drone to the Infested Boil in the middle of the Plains.

Stage 4: Kill Infested

Once the Toxin has been delivered to the Boil, it will begin spawning Infested, which you must kill. Each Eidolon Phylaxis added will increase the level of the Infested, though they are still very easy to kill.

Each Infested Catalyst added will cause a Hemocyte to spawn at equal intervals. For instance, with a full 4 Infested Catalyst added, a Hemocyte will spawn at 25%, 50%, 75%, and 99%. The last Hemocyte will always spawn at 99%, and must be killed to end the final Stage.

The Hemocyte is essentially a copy of second phase Lephantis, being vulnerable only when its heads move to attack. Notably however, it has a layer of Infested Sinew armour on top of its Fossilised health - weak to Radiation rather than the usual Corrosive. Additionally, as with Lephantis, the Hemocyte is invulnerable to status effects, so cannot have its armour stripped by Corrosive procs. As such, the only way to strip its armour is with the Melee mod Shattering Impact.

Running Solo, assuming minimal/no bugs and reasonable objective locations, I can get a full Plague Star run completed within 15 minutes. My best is around 12 minutes for a run. A coordinated, skilled team can easily complete a run within 10 minutes, probably below 8 minutes with some luck.

Rewards:

Completing the base Bounty will award 1000 standing. Each Eidolon Phylaxis and Infested Catalyst added will give an additional 250 standing, to a maximum of 3000 standing in one run. All rewards are handled by Nakak.

Hemocytes drop a Hemocyte Cystolith (used for Clan Dojo trophies) and a mod from the Hunter mod set (notably including Hunter Adrenaline [a better Rage], and Hunter Munitions [allows any Crit primary to inflict Slash procs]).

These rewards are handled like a Syndicate, requiring 6000 standing and some small sacrifices to reach the final level. Unlike other Syndicates, there is no Daily Standing Cap, so you can grind your heart out - and you might want to considering the rewards on offer.

Firstly, you can acquire Cetus Wisps, Eidolon Gems and all rare Plains fish parts except for Seram Beetle Shells. You can also acquire Fulmination (increased blast radius for secondaries) and Sacrifice (Sentinel sacrifices itself to revive you). Notably, Forma is available for 3000 standing, meaning you can get one for each run with full Infested Catalyst and Eidolon Phylaxis. The Snipetron is not available elsewhere, and both Exodia Arcanes are exclusive to the event. Additionally, there are four special Zaw parts, two of which are Strikes - Plague Keewar and Plague Kripath. They have higher Crit + Status spreads than regular Zaw Strikes, and also have innate Viral damage.

If you're new to the event, I would recommend the following initial purchases:

• Eidolon Phylaxis blueprint - to make future runs give significantly more Standing.
• Plague Keewar and Kripath blueprints - at least one of each, and ideally multiple if you intend to experiment further with Zaws.
• Sacrifice - a very useful Sentinel mod when you're playing Solo.
• Snipetron - it's a poor weapon, but not available anywhere else.

After those purchases, the two Exodia Arcanes are fun and exclusive (you'll ideally want 10 of each, to form a full Rank 4 Arcane), while Fulmination is exclusive though not very good. From here on, you're free to stockpile whatever you need. One Forma from a single run worth of Standing is an absolute steal if you can kill the Hemocytes at a reasonable speed, while the various resources mean you can reduce mining/fishing/Wisp hunting. However, it is more efficient to acquire those resources on the plains themselves, primarily from killing Thumpers.

Recommended Loadouts

Each of the four Stages has different requirements, so a variety of Warframes are useful.

Stage 1 requires fast travel, which can be mostly covered by just using the Itzal Archwing, but Archwings cannot be used in caves. The best Warframes that come to mind for speed and mobility are Nova's Wormhole (3), Zephyr and Volt, though there are more.

Stage 2 requires defending the Toxin Mixer, which is very easy. A defensive Warframe like Frost, Limbo, or Gara can be useful, but is by no means necessary.

Stage 3 requires escorting a Drone to the Boil. The Drone can be teleported ahead using Nova's Wormhole (3) or Loki's Switch Teleport (3). Alternatively, a Warframe capable of protecting the Drone such as Gara or Nezha with Safeguard can make this Stage easier, but no shorter.

Stage 4 requires killing a lot of Infested, and killing Hemocytes. The former is easily achieved, either with an AoE Warframe like Volt, Equinox or Saryn, or just with AoE weapons like Ignis (Wraith) or a Whip Melee. There are a lot of Infested spawned so killing enough to progress is usually very quick. Killing the Hemocytes is made most efficient by a mix of damage buffs and certain CC (though CC has diminishing returns against Hemocytes). Nova, Rhino and Harrow are Warframes that come to mind which are very useful against the Hemocytes. Notably, Titania's Dex Pixia are very strong against the Hemocyte as well.


Weapon-wise, the Hemocyte, like Lephantis is best damaged by weapons with high RoF and crit, but low(er) base Damage. Notably, this includes conventional Shotguns as the base Damage for each pellet is fairly low. Primary-wise, this means things like Prisma Gorgon, Prisma Grakata, Tenora, Vaykor Hek, Stradavar Prime and Soma Prime. Secondary-wise, weapons like Pyrana Prime, Aksomati and Twin Grakatas are well suited to the task.

For fastest time-to-kill on the Hemocytes, you want to strip their armour with Shattering Impact, and equip Corrosive damage on your weapons. By far the best Shattering Impact weapon is the Sarpa, as each of its ranged shots consists of 5 separate pellets, which can each proc SI. Unfortunately, the other gunblade Redeemer (Prime) is unsuitable, as its ranged shot deals purely base Blast damage.

My Loadout

My go-to loadout uses Nezha, Prisma Gorgon, a Crit Rattleguts and Sarpa.

Nezha's Warding Halo offers easy survivability, and can be cast on allies as well as the Delivery Drone. Fire Walker is a useful speed boost and light CC, while also dealing enough damage to kill lighter Infested in the last Stage. Blazing Chakram drastically increases damage dealt to tagged enemies, which can be used on the Hemocyte (though only lasts a short time).

Of the primaries I have, I've found the Prisma Gorgon to be the most effective against Lephantis/Hemocyte, thanks to its great crit (and a pretty nice Riven). Similarly, my Crit Rattleguts is one of my best options against Lephantis/Hemocyte, though Pyrana Prime is also a really good option. Sarpa, as mentioned before, is for stripping the armour from the Hemocyte with Shattering Impact.