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. The actual text of the prophecy is secured in the archives of the Bastion Serpentis, and Lord Inquisitor Anton Zerbe, the leader of the Inquisition in the Calixis Sector, 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.
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. The eerie phenomenon 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.
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.
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.
Excerpt from the Propheticum Hereticus Tenebrae
This excerpt (first four paragraphs only) from the first section of the Propheticum Hereticus Tenebrae talking about Komus has been shown to you by your Inquisitor:
Komus, the Tyrant Star, the Bringer of Destruction, the Harbinger of Chaos, will come to visit the worlds of these stars. Sometimes, he will shine his darkness brightly onto the souls of those he corrupts. Sometimes, he will not be seen and still bring about doom. And he will travel amongst these stars for aeons, aimlessly searching for the goal he cannot achieve, driven by the tortured souls of those that sought for salvation.
Finally, in the time of the twenty-first Maek’lor, the three of one will abet the one of three in his quest. They will rally those that know, those that hide and those that bring about, and they will seek to revive what has long been forgotten.
And so the twenty-first Maek’lor will see the Locks of Hyades reopened, and the Three Flames of The Enlightened Ones will burn again and they will guide the dead on their way home.
And at that time, Komus will rejoin these worlds once more and it will bear the doom that became its singular purpose so many millennia ago.