Warhammer 40k Wiki
Warhammer 40k Wiki

"Entry: ‘Obscuro’—The nature of the threat is either unknown, resists analysis, is deliberately hidden, or falls outside the normal categories of danger. This threat classification is also in rare circumstances applied to forbidden dangers of mankind’s own forgotten antiquity."

— Definitions of the Common Inquisitorial Threat Ratings, Tabernacle of the Conclaves Segmentum

The Tyrant Star appears in the sky of a Hive World in the Calixis Sector

The Tyrant Star, also known as Komus, is an uncategorised stellar anomaly found in the Calixis Sector of the Segmentum Obscurus. Komus appears as a black dwarf star whose arrival in the sky of a world is seen as an imminent herald of catastrophe, while the existence of the Tyrant Star is itself part of a wider prophecy called the Hereticus Tenebrae that is of great interest to the Imperial Inquisition. Unraveling this prophecy and the role of the Tyrant Star may be crucial to preventing a cataclysm that will consume not only the worlds of the Calixis Sector but perhaps the entire Imperium of Man.


The so-called Tyrant Star resists easy interpretation but certain key facts are evident. Komus is described in a doom-laden vision which speaks in apocalyptic terms of a "darkness" that will engulf the worlds of Mankind and ultimately devour all of human civilisation. The engulfing darkness will be preceded by signs and portents, so-called herald events, that will gradually transmute human minds and make them ready to embrace the darkness. Many believe this to be an obvious allusion to a rising of Chaos and the Warp, though this explanation is far from universally agreed. There are many considerable threats in the galaxy to the Imperium and the human race. The prophecy could as much apply to the Tyranids (some Imperial scholars note a repeated use of the word "devour" in the prophecy text) or the Eldar as to the Warp. However, given the Warp’s manifest ability to uncreate and mutate physical reality, much weight is given to this idea by the Tyrantian Conclave of the Calixis Sector. The actual text of the prophecy is secured in the archives of the Bastion Serpentis, and Lord Inquisitor Anton Zerbe only allows a very favoured few to examine the complete transcript.

In speaking of the herald events, the Propheticum Hereticus Tenebrae, as the manuscript is called, makes many references to "Komus" or the "Tyrant Star". Komus is said to be the harbinger, a portent of the encroaching darkness. It is said to be a "black sun" or a "halo of black flame". This preternatural harbinger is represented by an unholy rune, best described as a clawed bird’s foot. The rune has resisted specific translation and no previous occurrence of it has yet been found. Zerbe believes it can be no coincidence that the Calixis Sector is fraught with a curious, recurring phenomena: that of the "Spectral Sun". From time to time—no specific interval period has been identified—a monstrous "black sun" matching the prophetic descriptions of the Hereticus Tenebrae has mysteriously appeared in various locations throughout the sector.

No two appearances have been quite the same but the pattern of visitation is usually this: with little warning, a ghostly star apparently emitting black flames and esoteric, unknown forms of radiation, spontaneously materialises in a planetary system, shines malevolently for a few days, and then, just as mysteriously, vanishes without trace. The visitation is accompanied by psychic disturbance, geological upheaval and sociological problems on inhabited worlds, including mass rioting and unrest. Most often, the Spectral Sun actually eclipses a star system’s natural star, as if possessing it, causing consternation and panic on the orbiting worlds as their sun goes black. However, the Spectral Sun has also on occasion appeared less directly—a strangely bright star at night, a phantom corona around a moon—before disappearing. No Imperial astronomer of the Adeptus Mechanicus has successfully explained the eerie phenomenon. It belies human science and has thus far evaded close investigation. Its visitations cannot be predicted. The Tyrantine Cabal believes that the Spectral Sun phenomenon is the Tyrant Star, Komus, as it so closely matches various descriptions in the prophecy. Some suggest the Tyrant Star is the ghost image of some stellar body in the Immaterium, shining through the worn fabric of material space. Others say it is a mirror image, a Warpspace star that is partially translating into realspace, trying to find a way through. Yet others claim that the Tyrant Star is an artificial body, driven by xenos engines and technological mechanisms Mankind cannot comprehend.

Whatever the truth, the phenomenon is a fact. It has manifested eighteen times in the Calixis Sector during the last century (8th Century of the 41st Millennium). Every single visitation has caused public unrest and geological instability. Where the Tyrant Star appears, earthquakes and volcanic upsurges follow. A world will experience a violent period of upset and political revolution prior to its appearance. Many more psykers than usual will be born or become active. Mutation will occur more often. These things will usually take place in the two or three months leading up to a manifestation. Signs and portents will be widespread: these generally are a matter of birthmarks, odd runic sigils appearing upon walls without explanation and the rise of fanatical religious cults. Some sources also describe premonitory half-sightings, fleeting glimpses of the black-flamed sun in mirrors, pools, puddles or even on the surface of wine or water in drinking vessels.

Mass panic and insanity precede a visitation of the Tyrant Star. No one has been able to explain how it appears and covers a solar system’s natural star with its noxious black smoke. Sometimes, disorder and civil unrest lead to nothing and, for all the portents and cues, the Tyrant Star never actually appears, though this may be because it has manifested in a way that is hard to detect. On at least two recorded occasions, the Tyrant Star has appeared merely as a distant star above a world, no larger than a morning star, instead of eclipsing the local sun.

The Tyrantine Cabal believes it is a vital part of its work to trace and investigate these visitations, and to actually be on site to witness a manifestation. Zerbe hopes that important data may be gathered during a genuine sighting. In the Calixis Sector at large, the visitations are a matter of myth and rumour. The Inquisition has carefully suppressed any official confirmation of the phenomenon.

As a consequence of its long history in the Calixis Sector, the Tyrant Star appears throughout the heraldry and decoration of structures commissioned by the Haarlock Dynasty of Rogue Traders. The Haarlocks have an unclear yet potent connection to the Star, and their family members made use of its energies within their complex devices and heretical living weapons. Erasmus Haarlock has the strongest known connection to the Tyrant Star, and is imprisoned within its depths, awaiting release through the manipulation of ancient structures on Dusk.

Cursed Space

Inquisitors are empowered to go wherever they want in the prosecution of their duties. An Inquisitor might travel from one end of the Imperium to the other, and indeed beyond its borders, in the course of a long career. Yet, it has been noted by many, that the Calixis Sector attracts the agents of the Inquisition, and somehow enthralls them, almost as an insect trapped in amber. In an entire galaxy seething with conspiracy and torn apart by war, many have asked why the Calixis Sector should attract and hold the attention of so many Inquisitors, and why it has claimed the lives of countless of their number. Perhaps the answer lies in the Hereticus Tenabrae, the prophecy that foresees the extinction of Humanity, its crucible the Calixis Sector. Certainly, the Calixis Sector breeds cults and heresies at an alarming rate, and many within the Ordos Calixis believe that the dread Tyrant Star must surely be responsible. Perhaps the truth will never be known until it is too late, and the galaxy burns.


In Greek mythology, Comus or Komos is the god of festivity, revels and nocturnal dalliances. He is a son and a cup-bearer of the god Dionysus. Comus represents anarchy and chaos. His mythology first became prevalent in the later period of Classical antiquity. During his festivals in Ancient Greece, men and women exchanged clothes to symbolise the anarchy he brought. He was often depicted as a young man on the point of unconsciousness from drink. He had a wreath of flowers on his head and carried a torch that was in the process of being dropped. Unlike the purely carnal wilderness god Pan or the purely intoxicated Dionysus, Comus was a god of excess.


  • Dark Heresy: Ascension (RPG), pg. 160
  • Dark Heresy: Core Rulebook (RPG), pp. 317-322
  • Dark Heresy: Disciples of the Dark Gods (RPG), pg. 8
  • Dark Heresy: Tattered Fates - Book 1 of the Haarlock's Legacy Trilogy (RPG)
  • Dark Heresy: Damned Cities - Book 2 of the Haarlock's Legacy Trilogy (RPG)
  • Dark Heresy: Dead Stars - Book 3 of the Haarlock's Legacy Trilogy (RPG)