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Retrovirus The Turncoat's Kit
Retrovirus stores the cells it kills and brings them back as allies. It can also slip into latency, where nothing can find or hurt it.
The Turncoat · Level 4 unlock
Retrovirus
Turns the immune system against itself. Cells killed by its shots go into a reservoir, and Integration Surge releases them as allies. Latency hides it completely.
Role: The Turncoat. Colour: pink-redBecomes available at level 4, through the Reverse Transcriptase Capture mutation Move speed 188, about the same as Influenza A; same health, damage and fire rate Passive: +50% damage to bosses and Killer T cellsStarts every run with Integration Surge charged and a full reservoir Signature (LATENT): Latency hides you for 4 s, you can't be hurt, and the cells around you witherUltimate: Integration Surge releases stored cells as allies and hits everything within 300 for 6x your damageFrom the Gut on, kills by your shots also build up kamikazes Compare the playable viruses The Retrovirus in the Lymph Node On this page 9 Viral Reservoir Charged Start Immune Hunter Integration Surge Captured Allies Guardian Macrophage Kamikazes Latency Retrovirus Lab branch Cells killed by your auto-attack shots are stored in a reservoir, ready to be released by Integration Surge.
Holds 6 cells (Integrase Efficiency adds +1 per level); the HUD shows STORED x/6 and RESERVOIR FULL Only kills by your own auto-attack shots count Antibodies, summoned cells, bosses, mini-bosses, Killer T cells, drug capsules and vaccines are never stored From the Codex Leftover DNA from ancient retroviruses that infected our ancestors and became a permanent part of the human genome.
Fun fact: Around 8% of human DNA comes from ERVs. Some of it even helps build the placenta.
Endogenous Retrovirus (ERV) in the Codex Every run starts with Integration Surge charged and a full reservoir.
The starting reservoir is filled with random immune cells (neutrophils, monocytes, B cells, NK cells, macrophages, basophils, eosinophils), always including at least one macrophage Every other "start with your ultimate charged" effect banks one more charged Surge, with its own fresh full reservoir, ready right after you use the first (HUD: ULT +n) From the Codex A fictional retrovirus inspired by HIV: it infects the immune system's own CD4 T cells and macrophages and slowly wears it down.
Fun fact: HIV copies its RNA genome into DNA and stitches it into the host's chromosomes, so infected cells carry it for life.
Retrovirus in the Codex Built to infect immune cells, Retrovirus tears into the big ones.
All damage to bosses and Killer T cells is +50% From the Codex The giant immune cell guarding the way to the next organ.
Fun fact: From the third organ on, every boss also has a signature skill on its own random clock, aimed at you.
Bosses in the Codex Releases every cell in your reservoir as an ally beside you, and hits everything nearby.
Every hostile cell within 300 takes 6x your damage (plus the +50% against bosses) Each stored cell comes back as an ally with 60% health that fights for 18 s At most 15 allies at once; a stored cell past the cap never forms With an empty reservoir it still hits: "The immune system turns on itself" Cytopathic Burst (Lab) adds +50% Surge damage per level From the Codex A retroviral enzyme that copies RNA into DNA, the reverse of the usual flow of genetic information.
Fun fact: It's so error-prone that HIV mutates constantly, which is why it escapes the immune system and drugs.
Reverse Transcriptase in the Codex Released cells wear your green colour and hunt down the nearest hostile cell.
Allies strike cells they touch every 0.5 s Every captured cell except the macrophage is a striker that hits 1.6x harder Allies fight for 18 s (Viral Reservoir Lab: +5 s per level; Provirus Lab: until the room is cleared) Syncytia (Lab): allies explode when their time runs out (45 damage in a 95 radius)From the Codex A retroviral enzyme that copies RNA into DNA, the reverse of the usual flow of genetic information.
Fun fact: It's so error-prone that HIV mutates constantly, which is why it escapes the immune system and drugs.
Reverse Transcriptase in the Codex A captured macrophage is your tank: it guards you and taunts cells into fighting it instead of you.
Every 1 s it taunts up to 3 cells within 170; they chase it until it dies or its time runs out Never taunts bosses, mini-bosses or Killer T cells When a hunting cell comes within 220 of you, it dashes back at 3.5x speed to stand between you and the threat, taunting as it arrives From the Codex A large white blood cell that eats pathogens and dead cells by phagocytosis, then shows pieces of them to other immune cells.
Fun fact: The name comes from Greek for "big eater".
Macrophage in the Codex From the Gut on, every cell your shots kill adds a kamikaze to a store that releases itself when full.
Store holds 5 (HUD: KAMIKAZE x/5, then KAMIKAZES READY)When the store is full and a hostile cell is present, all 5 burst out around you Each rushes the nearest cell and explodes on contact, or after 10 s, for 35x your damage in an 85 radius Their blasts grow with your captured-cell damage milestones From the Codex A Y-shaped protein made by B cells that binds to a specific part of a pathogen, marking it for destruction.
Fun fact: Your body can make billions of different antibodies.
Antibody in the Codex Go dormant for a few seconds. Nothing can find or hurt you, and the cells around you wither.
Lasts 4 s (Deep Latency Lab: +1 s per level)Detection drops by 30 Hunting cells lose your trail, even ones that arrive mid-latency (bosses and Killer T cells keep tracking you but can't hurt you) You can't fire while latent Every 0.5 s a pulse hits every cell within 130, bosses included, for 80% of your damage From the Codex A dormant state where a virus hides inside a cell without making new copies, invisible to the immune system.
Fun fact: Latent HIV reservoirs are the main reason the infection can't yet be cured.
Viral Latency in the Codex Retrovirus's own Petri Lab upgrades.
Integrase Efficiency (3 levels): store +1 more cell per levelDeep Latency (3 levels): Latency lasts +1 s per levelViral Reservoir (3 levels, 1 RNA): allies fight +5 s longer per levelSyncytia (1 level, 2 RNA): allies explode when their time runs outSurge Reach (3 levels): Integration Surge radius +20% per levelRapid Transcription (3 levels): ultimate charges 15% faster per levelCytopathic Burst (2 levels, 2 RNA): +50% Surge damage per levelProvirus (1 level, 3 RNA): Surge allies stay until the room is clearedFrom the Codex Permanent upgrades. The core ones are shared by every virus; ability and ultimate ones belong to one virus.
Fun fact: Pick an upgrade to see every level and milestone.
Petri Lab in the Codex 
