Helminth is the Infested entity within the Helminth Infirmary, responsible for the biological functions of the Orbiter and Landing Craft. Relics from the Orokin Empire indicate that the Helminth has a history going back much further. Helminth's dialogue is only audible as low growls and rumbles, translated into text by subtitles.
When first entering the Helminth Infirmary
The Helminth Infirmary will only open if the Tenno is controlling a Nidus warframe, or any warframe that has a fully developed cyst on its neck. Upon entering, the Helminth is dormant, but Ordis will comment on the Infirmary and Helminth itself. The longer the Tenno stays in the room, the more Ordis will elaborate.
Ordis: "Disgusting, is it not, Operator? Ordis would enjoy—purging this—uh, cleaning this room, but sadly this… vile mass serves you and your warframes. A necessary evil."
Ordis: "Vile. Putrid. This… 'thing'… is responsible for the biological functions of the Orbiter! A strange design. Why would I be built with such a flaw?"
Ordis: "Ordis cannot remember, but there does seem to be a… relationship… between your warframes and the Infestation. I would be careful in here, Operator. Domesticated or not, Ordis does not trust this thing."
Ordis: "A strange biological archive here. I cannot explain it, Operator; as you know, I have sustained memory system damage. Ordis recommends leaving at once and welding the door shut."
On first sitting in the chair
There is a chair in the middle of the Infirmary, integrated with the Infestation. Upon sitting in the chair as Nidus for the first time, Helminth will awaken and use one of the chair's Infested tendrils to inject the Nidus warframe in the neck. This will infect the warframe with the Helminth virus, and it will develop a cyst over the next 7 days, as well as infecting any other Tenno it comes into contact with.
(upon sitting in the chair) Ordis: "Operator, no! Have you lost your mind?!"
(after receiving injection) Helminth: ("We awaken, Master.")
Ordis: "What was that? Is it… talking? What did it say?"
Helminth: ("I wish to serve, yet I am weak. Time heals the mind.")
When entering the room with a warframe
After Helminth awakens, it will speak to the Tenno any time they enter the Infirmary, whether with Nidus or a different, infected warframe.
("The Meridians awake. The vital pentatonic.")
("Forgive me, my sting, Master.")
("I am weak, Master.")
("Living substances is our domain. How will we serve you?")
("Feed me… Master.")
("We are life, Master. But also death.")
("All that lives is coiled within us. We will consume, Master, if you wish it.")
("We… breathe for you. Bleed for you. Feed for you.")
("We germinate, for the Master… within the Master.")
("Master, only my voice has returned.")
("We are as one.")
When entering the room with the Operator
The Infirmary door can be opened with an eligible warframe and then held open by positioning the warframe in the doorway. If the Tenno Transferences out and walks into the Infirmary as the Operator, Helminth will react to the Tenno's true form, including comments on the Tenno's alignment from their choices during the main story quests.
("The demon is awake? How?")
("We fear nothing but the Void demon.")
(Sun alignment) ("Light shines within this demon.")
(Neutral alignment) ("This demon walks the shadow's edge.")
(Moon alignment) ("Shadows grow within this demon.")
When removing the cyst
Once a cyst is fully grown, it can be removed by sitting in the Helminth Infirmary's chair and having it lanced by the same Infested tendril that was used to create it.
(upon sitting in the chair) Ordis: "Operator, no! Have you lost your mind?!"
(after removing cyst) Helminth: ("Why do you reject my beauty?")
When the Tenno reaches rank Associate with the Entrati, they can purchase the Helminth Segment blueprint from Kermerros. The Helminth Segment requires 20 Adramal alloy, 5 Saturated Muscle Mass, 15 Ganglia, and 5 Purple Velocipod tags, and costs 50.000 credits and 24 hours to build. When it is built and installed, it unlocks further functionality and dialogue from the Helminth, along with the ability to rename it, and to enter the room with an uninfected warframe.
(upon installing the Helminth segment) ("The potential you have granted me… hurts… and yet… I hunger to make… and to unmake.")
(if the Tenno says "Feeding?") ("I can secrete Infusions that will make you stronger, more versatile… but to do this, you must feed me…. Will you feed me?")
(if the Tenno says "Subsume?") ("When we're both ready, yes. Your warframe, my sacred kin, can be absorbed…. It will blossom within my body, granting me a trace of its power. A power I can pass on to others….")
(if the Tenno says "Why are you on my ship?") ("Who nurtures you in your times of rest? Who restores your battle-torn frame, day after day after day? Whose milk enriches your kindred flesh with endless strength and vigour? It can only be me.")
Feeding the Helminth
(desired resource) ("To a deep crevasse is this gift reserved.")
(desired resource) ("My servitude in thanks to this demon. My Master.")
(desired resource) ("Yes. Plentiful mucus. Do you see?")
(neutral resource) ("Master feeds. I change. Fresh secretions threaten at every pore.")
(neutral resource) ("Yes, Master. I swell… and bloat.")
(neutral resource) ("You give me life. Why?")
(neutral resource) ("I give painful thanks. In return what does this demon wish?")
(neutral resource) ("Yes….")
(neutral resource) ("I distend with your gifts.")
(neutral resource) ("Life boils within.")
(neutral resource) ("I tremble with peristalsis.")
(undesired resource) ("Master's excess I off-gas as ammonia. And methane.")
(undesired resource) ("I beg this demon: do not feed me that.")
(undesired resource) ("Please, Master! Too much! Bladders and sac-stores become toxic!")
(if full) ("Sacs, stomachs, bladders – all full. I grow torpid.")
(if full) ("My hunger is contained.")
(if full) ("This demon satisfies me.")
Subsuming a warframe
("Mine. For the demon: this.")
("This demon's gift shall rest within me forever. In thanks I give.")
("I accept the demon's offering. Will it accept mine?")
Selecting an ability when the Helminth lacks the necessary secretions
("Demon has food. GIVE.")
("When will Master feed me? WHEN?")
Infusing an ability
("Accept gifts, Master, but please... ask not from whence they come.")
("I quiver to gift this demon in return.")
("You are forever changed. Is this demon pleased?")
("Our pact has borne ripe fruit.")
("We grow closer to becoming one, I and this demon.")
("Demon… for you.")
When the Tenno reaches rank Family with the Entrati, they can purchase the Helminth Invigoration Segment blueprint from Kermerros. The Helminth Segment requires 20 Tempered Bapholite, 10 Pustulent Cognitive Nodules, 15 Pustulite, and 5 Vizier Predasite tags, and costs 50.000 credits and 24 hours to build. When it is built and installed, it unlocks the ability to "invigorate" three random warframes per week with a set of random, powerful buffs. These buffs, once invigorated, last 7 days.
(upon installing the Helminth segment) ("Ah! A new agony! A new spasm! The cellular archive opens… kinship deepens… I shall craft, concentrate, concoct. Serums for the children of the Ancestor Worm!")
This dialogue line is reused when the Tenno instals the Archon Shard segment for the Helminth, available after completing the Veilbreaker quest.
Invigorating a warframe
("I pulse. I ooze. I give you of myself.")
("My finest secretions, Master. For you and you only.")
("Drink deep of me. Luscious it is and pleasing to the entrails.")
("My plasma shall be your quickening. My mucus, your nourishment.")
("What you have fed me, I return to you transmogrified!")
Leaving the chair
("I await the return of this demon.")
("I palpitate in your absence.")
("Our work never truly ends.")
The Helminth is referenced indirectly by Ballas in the Sacrifice quest, and more directly in the Octavia Prime trailer. Red Veil crewmembers will mention it by name, as Kermerros does when he informs the Tenno of the Helminth Invigoration Segment. It is briefly mentioned during the New War quest.