Diverticulum are poison filled polyps that Tetarti creates. They must be treated before the real battle with Tetarti starts. Diverticulum slowly swell in size. Once they reach full size they will begin dispersing toxins and harming the patient's vitals. Diverticulum can only be created when a Tetarti body is injected with the wrong antigen.
They are treated by injecting the diverticulum with the antigen that matches its color. Then, before the antigen wears off, the diverticulum must be excised and removed promptly. The wound left behind must then be sealed with the synthetic membrane.