"Nature mandates that mankind will eventually succumb to poison. However, humans created their own poison, called medicine. It's delusion to believe you can toxify nature to avoid your fate." -Adam
"'s delusional to dismiss peoples' deaths as 'fate.'" -Derek Stiles
"Your poison isn't natural OR medicinal; it's madness!" -Naomi Kimishima

Tetarti is the fourth strain of GUILT encountered in Under the Knife and Second Opinion. Greg Kasal is the first known host of Mature Tetarti. Upon learning that it is not treatable, Derek and Angie set out to find the antigens required to fully treat mature Tetarti. While immature Tetarti attacks alone, mature Tetarti comes in trios, initially appearing as types V, P, and H, colored purple, green, and yellow, respectively.

Types of Tetarti Edit

Immature TetartiEdit

Immature Tetarti must be incapacitated with a special serum. After it's injected, it will dive into the organ. Use the ultrasound to find it, then cut it with the scalpel to bring it to the surface to repeat the serum injections until it's defeated. Grab it with the forceps and place it on the tray, then cut down the middle and drain the fluid from the Immature Tetarti.



Three abscesses caused by Tetarti

Mature Tetarti will have formed 3 poison-filled diverticulum that will swell in size until they are either injected with the corresponding color antigen and excised or reach full size, whereupon the diverticula will release a cloud of toxic gas and deal a large amount of damage to the patient. After all three abscesses are removed, the three Mature Tetarti will emerge.

Mature TetartiEdit


Mature Tetarti showing colors.

Mature Tetarti require a decent memory, good vision, and a steady hand. At the beginning of an operation, as the Mature Tetarti are emerging, they will show their colors for a moment, memorize them and inject the matching color antigen into each Mature Tetarti carefully, but quickly. After the first is injected, a hidden timer will start. If the other two are not incapacitated quickly enough, all three will submerge into the organ and reemerge free of the antigen's effects.

Mutated A TetartiEdit

In Second Opinion, starting from 6-3, Mutated A Tetarti randomly appear without showing its color, while moving and releasing toxic mist at a much faster rate than usual. They also will not dive into the organ or stop releasing toxic gas until all 3 are injected. Injected Mutated A Tetarti will also continue to move in order to confuse the player further - and the effects of the antigen can wear off if the player is too slow in injecting them all.

Mutated B TetartiEdit

In Under the Knife 2, Tetarti's mutation adds a total of 2 new colors to the mix. The blue variant is introduced in 5-2, while the black is added in 6-3. The appropriate Tetarti antigen will be added to the Tetarti vials where appropriate as they've been developed offscreen. Otherwise, the Tetarti will behave like normal, and only three bodies will manifest at a time.

Aletheia TetartiEdit

Aletheia Tetarti come in green, yellow and purple. It can be difficult to see the color. If you take too long or inject the medication into the wrong Aletheia Tetarti, they will move around Aletheia and form diverticula.


Under the Knife​Edit

Episode Patient Organ Type of Tetarti
4-2: Race for the Cure Joe Faison Liver Immature Tetarti
Ray Barnett Stomach Immature Tetarti
Donald Grey Pancreas Immature Tetarti
Thomas Epps Stomach Immature Tetarti
4-4: Stepping Up Greg Kasal Liver Mature Tetarti
5-4: GUILT Evolves Eric Dorian Left kidney Mature Tetarti
6-5: Fourth Sin Unnamed boy (Fourth Sinner) Left lung Mature Tetarti
X-4: Tetarti Unnamed man Liver Mature Tetarti

Second OpinionEdit

Episode Patient Organ Type of Tetarti
4-2: Race for the Cure Joe Faison Liver Immature Tetarti
Ray Barnett Stomach Immature Tetarti
Donald Grey Pancreas Immature Tetarti
Thomas Epps Stomach Immature Tetarti
4-4: Stepping Up Greg Kasal Liver Mature Tetarti
5-4: GUILT Evolves Eric Dorian Left kidney Mature Tetarti
6-3: Relapse Kathy Lyans Liver Mutated A Tetarti
X-4: Tetarti Unnamed man Liver Mutated A Tetarti

Under the Knife 2Edit

Episode Patient Organ Type of Tetarti Other GUILT Present
5-2: Retaliation Bao Nguyen Liver Mutated B Tetarti None
6-3: Widespread Fear Mick O'Mally Liver Mutated B Tetarti None
6-7: Tragedy Heinrich von Raitenau Liver Mutated B Tetarti None
7-7: Mother of Sins Reina Mayuzumi Heart Aletheia Tetarti Aletheia
X-2: Tetarti Unnamed man Liver Mutated B Tetarti None
X-7: Aletheia Unnamed woman Heart Aletheia Tetarti Aletheia

Stats and AttacksEdit

Attack Used by Infromation
Toxic Mist Immature Tetrarti Tetarti periodically releases toxic mist matching their own colour as they roam about the organ.
Mature Tetrarti
Mutated A Tetarti
Mutated B Tetarti
Desperate Toxic Mist Immature Tetarti Immature Tetarti runs around the organ, releasing toxic mist as it goes, until it defeats itself.
Mutated A Tetarti Mutated A Tetarti may continuously release toxic mist without displaying their colours. The player can identify which antigen to use based on the colour of the mist.
Diverticula Mature Tetarti If a Tetarti body is injected with the wrong colored antigen, a diverticulum will form corresponding to its own colour.
Mutated A Tetarti
Mutated B Tetarti
Aletheia Tetarti Aletheia Tetarti creates diverticula while moving around Aletheia.
Counterattack Immature Tetarti When Immature Tetarti is inside an organ, when pulled out with the scalpel, Immature Tetarti will create a small laceration.


  • Estimate just how much serum needs to be injected into Tetarti to damage it in order to save time while attacking Tetarti. It usually ranges about 1/3 to 1/4 of a syringe.
    • This knowledge is particularly vital in Under the Knife 2's X-2, where the Tetarti only emerge for a short period of time before diving into the organ.
  • Don't attack Tetarti when they get too close to each other. You will be likely to hit two Tetarti at the same time with one antigen, causing diverticula. This only applies for Under the Knife - Tetarti turn away when they bump into another Tetarti in Second Opinion and Under the Knife 2.
  • A difficulty faced while attacking Tetarti, particularly in Second Opinion, is that it is easy to miss with the injection if Tetarti suddenly turns. For best effect, aim at Tetarti's head, preferably while it is not near the edge of the organ or any other Tetarti.
  • You can pause the game during the time Aletheia Tetarti are showing their colors. They will then move to the next position counterclockwise. Use this information to figure out which Aletheia Tetarti needs which serum.


  • Japanese versions of Trauma Center have confused Tetarti with Triti, resulting in these two GUILT having the other's name in that version.
  • It is difficult to determine the colour of the diverticula in Under the Knife without letting them grow first. Later games allow the colors to be clearly seen.
  • If you look closely, Tetarti looks like the Caduceus symbol.
  • Tetarti is based off Liver flukes, a species of flatworm that feed off of the blood and bile of a wide variety of mammals. The symptoms of Tetarti and a Liver Fluke infestation are very similar: fatigue, weight loss, jaundice, abdominal pain, and a backed-up liver. Similar to Tetarti which can cause diverticula every 15-30 seconds, Chinese liver flukes lay eggs in the liver every 1-30 seconds. Its cousin, the blood fluke, is much more deadly and also infects the bladder, spleen, and major blood vessels.
    vde Diseases and Conditions
Common Conditions AneurysmAppendicitisBurnCardiac ArrestCholelithiasisForeign ObjectHemorrhageInflammationLacerationTumor
GUILT KyriakiDefteraTritiTetarti (Diverticulum) • PemptiParaskeviSavatoBliss
Stigma CheirSomaOpsOnyxBrachionCardia
Post-GUILT Syndrome Post-KyriakiPost-TritiPost-PemptiPost-Savato
Neo-GUILT NousBythosSigeAletheia
Other Rosalia Virus (Twisted Rosalia) • Costigar DiseaseVaimahse Fever
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