Tholians are an extremely xenophobic, non-humanoid civilization. The Tholian interstellar state was the Tholian Assembly, which neighbored the Klingon Empire and the United Federation of Planets.

Species Physiology

Tholians are a crystalline-based species with a hard outer carapace through which a fluid can be seen circulating murkily. Approximately the same height as a human, they more closely resemble insects or crustaceans, having six thin legs with articulated with joints, each attached at the base of the torso in a radially symmetric arrangement, and each leg ends in a multi-toed foot. They also have two arms; each with joints analogous to the humanoid elbow and wrist, and each arm ending in a multi-fingered hand. There is a slightly visible neck covered by a semitransparent dome membrane that shields a faceted mantis-like heads with two triangular eyes.

Biologically, Tholians are almost living mineral formations, encased in a faceted carapace made completely of a crystal similar to quartz. This provides a natural armor that absorbs impacts made upon it from either kinetic or energy attack. However, there is a fluid medium beneath the carapace that supports metabolic processes. A typical Tholian possesses both male and female sex organs.

Tholian biology requires high temperatures around 480 Kelvin (207 °C, 404 °F). They can tolerate lower temperatures for a brief period of time, but if they are exposed to temperatures around 380 Kelvin or less, their carapace will fracture. In temperatures even lower, a Tholian can freeze solid and shatter.

Tholians communicate primarily through a series of clicks and chirps. They are also naturally able to emit various forms of radiation, which they can modulate. In this way, they can use their crystal bodies as living communicators which could resonate a harmonic signal for others of their kind to detect. In this fashion they can even call for assistance if from a ship journeying through Tholian space.


Tholians are extremely xenophobic. While there are stories of Tholian explorations of the galaxy dating back to their earliest recorded history, most of the species harbor an intrinsic distrust of aliens, with whom they find it distasteful to interact. As a result, knowledge of their society is limited. It is believed that the species have a hive culture with a system of specialized castes, though it is unclear if this was a rigid system fixed at birth or if individuals could transition to fill different designated caste functions.

It is known that Tholians place high value on accuracy and precision. This extends to prizing punctuality and honesty as expressions of accuracy in their relationships. It is also likely the reason that their borders are not fixed as they adjust them every eight cycles to account for the movement of star systems and astronomical objects within their claimed space. In early relations with the Federation, this was not understood by the nearby humanoids, who became victims of Tholian aggression over this territory. This led to a prolonged period of conflict, with many truces seemingly broken on the basis of this misunderstanding over definitions of territory.

Despite their xenophobic impulse toward isolation, Tholians did engage in intergalactic trade. Tholian silk in particular was highly prized commodity.


Brief Canon History

The government of the Tholians was known as the Tholian Assembly. It was known to execute outsiders caught entering Tholian space without their consent. The Assembly was also known to annex systems outside Tholian space, to further isolate their territory.

Until the mid-22nd century, the Vulcan High Command had only limited contact with the Assembly. First contact with Earth occurred in 2152, when the Tholian Assembly made an unusual move: traveling far beyond their territory, they actively sought to possess a 31st century Earth vessel discovered by the United Earth starship Enterprise NX-01. Four Tholian ships intercepted and disabled the combat cruiser Tal’Kir, while it waited to rendezvous with Enterprise. They, in turn, attacked and defeated a Suliban Cabal fleet that was in pursuit of the arriving Earth ship. They then successfully removed the pod from Enterprise’s possession, only to have the pod return to its proper time moments later.

Occasional conflicts between the Tholian Assembly and the Federation continued over the next century, with Tholians attacking Berellium in the 2250s. In 2268, the Federation starship USS Defiant responded to a false distress signal originating from mirror universe Tholians and entered a region of space which had just been annexed by the prime universe Tholians. This region contained an interphasic rift, and when the starship USS Enterprise discovered the Defiant, it was trapped in a spatial interphase. The leader of the investigating away team, Captain Kirk, crossed over into the mirror universe. Shortly thereafter, a Tholian ship intercepted the Enterprise, demanding that it leave Tholian territory. At the request of First Officer Spock to be allowed to rescue Kirk from the Defiant, Tholian Commander Loskene allowed the Enterprise and its crew a small timeframe before they were required to withdraw. Because the Enterprise crew was unable to rescue Kirk in the time provided, though, the Tholians opened fire, damaging the Enterprise. A second Tholian starship soon arrived and the Tholians then attempted to trap the Enterprise in their web. The Enterprise, however, was able to recover Kirk and escape successfully, without actually falling victim to the web.

In 2271 the Federation made a formal announcement in recognition of ongoing diplomatic ties between the two powers. However the Tholians’ contact with the Federation over the next century was sporadic but characterized by intermittent conflict. In 2353, the Tholians destroyed a Federation starbase and Starfleet considered the Tholians sufficiently dangerous as to warrant the development of Tholian-based battle simulations in the mid-24th Century.

In 2372, a Tholian observer was killed in the bombing of the Antwerp Conference on Earth by a Dominion infiltrator. Despite this, the Tholians signed a non-aggression pact with the Dominion the next year and remained neutral throughout the ensuing Dominion War.

Proposed Post-War History

In 2381, the Tholians were the senior partners in the Tryphon Pact, an alliance with the GornBreenTzenkethi, Kinshaya, and the Romulan Star Empire, set up in competition with the powers of the Khitomer Accords.

Key Facts

Facts Table
Home Planet:Tholia
UFP Status:Non-member

With the Hobus supernova and the dissolution of the Typhon Pact, the Tholians did maintain loose ties with the Gorn Tzenkethi. The last hold-outs of the Pact, the three powers continued to share limited resources for several years. While the Gorn’s relations with them have cooled, the Tzenkethi and Tholians remain uneasy allies due to the potential threat of a resurgent Cardassian Union.