Sikozu Svala Shanti Sugaysi Shanu (called Sikozu) is a Kalish who grew up in Scarran-controlled space. She becomes an expert (albeit a book expert) on Leviathans, and eventually goes to work for a pirate group who harvest toubray (nerve) fibers from Leviathans. She meets up with Crichton while he is aboard the Leviathan Elack in the Leviathan's sacred burial space; she led the pirates there and they subsequently try to kill her to prevent her telling anyone where the burial area is. Crichton nicknames her "Sputnik" due to the shape of her hairstyle when they met. There is initial confusion at their meeting because she cannot tolerate translator microbes and so must learn all languages by hearing them. This may not be a species trait, given that she is later exposed as a Bioloid agent, and could be a consequence of that process instead. She is extremely intelligent and picks up information very quickly. She can "change her centre of gravity" so that she can walk on walls and ceilings, and she can easily reattach limbs that have been severed. She has to eat only a few times a cycle (year).
She is extremely arrogant, a self-styled polymath who constantly belittles those around her. While her knowledge about technology, species, history, and the galaxy in general is vast, it is mostly academic. She is extremely naive and unknowledgeable about how things function outside a controlled environment (such as learning Leviathan physiology strictly via studying and not understanding that the floorplans of the biomechanoids vary as a result of passenger preference). Sikozu's sense of self-preservation is foremost in her mind, and so she is prone to switching sides in any conflict with no notice and seemingly no premeditation other than ad hoc judgments on who currently holds the greatest advantage. This makes her true loyalties (if any) uncertain.
Sikozu accompanies Crichton as he reunites with his crewmates from Moya, and she gradually allies herself with Scorpius, whom she initially seems intrigued by both because he saves her life and because he is arguably the most powerful and intelligent person on Moya. (He is the first mind Sikozu has known who she acknowledges as her equal or superior.) They eventually become lovers and she takes a place at his side when he is kicked off Moya. Just prior to the Scarran-Peacekeeper war, it is revealed that she is a bioloid (an android) and a double-agent. She is working with the Kalish resistance to free the Kalish from Scarran servitude, and as such was specially bioengineered to be able to hover in the air and release intense radiation heat rays from her body that destroy Scarran heat producing glands, rendering them weak and vulnerable. She is also able to direct this energy in smaller bursts via her hands when necessary. This radiation seems to still be harmful, although to a lesser degree, to Scarran hybrids such as Scorpius. When using her power in his presence, she instructs him to take cover and not to look at her.
Late in the war, it is revealed that Sikozu is a spy for the Scarran Empire in exchange for a promise from them to free her people from servitude. Scorpius assaults her after revealing his knowledge about her betrayal and leaves her to die on the water-planet, Qujaga. This development is foreshadowed in several earlier episodes: At their first meeting, Chiana thinks that Sikozu is a spy because she has Scarran currency and speaks Scarran. Sikozu explains this by saying that her people are from Scarran-controlled space. In a visit to an unrealized reality, Crichton — in that reality, a ranking Peacekeeper officer — is forced to execute Sikozu after she is revealed to be a Scarran spy.