Kain encountered tales of the entity throughout Blood Omen: Legacy of Kain, with tales of the cult mentioned by Villagers of various towns. While exploring Avernus Cathedral and its Hell dungeon in Defeat Azimuth Kain stumbled across a Secret altar dedicated to the worhip of Hash'ak'gik. [Blood Omen/8]
The shrine room was gory and chaotic, and it contained a blood-stained tome which read as follows:
- "And Hash'ak'gik spoke to the world, and all who heard trembled.
"Bring me your first born, and shed their blood on the altar of the world, so I might take nourishment from them.
Do this without question, or suffer my wrath for eternity."
And its will was done."
- ―Hash'ak'gik's altar[src]
The floor of this altar room was decorated with a demon-like image, but Kain had yet to recognize its significance.[Blood Omen/8] When he confronted Mortanius at the end of his quest, he realized that the Death Guardian had been possessed by a malevolent entity - an entity which, through him, had orchestrated the death of Ariel and the corruption of the Pillars. As he died, Mortanius's body was transformed by the entity, taking on the shape of the monster depicted in the shrine's image. It was the "Unspoken" which Ariel had warned him to be wary of; he defeated it handily.[Blood Omen/12][Blood Omen/2]
When Raziel later visited the Avernus Catacombs in Legacy of Kain: Defiance, he discovered the truth behind Hash'ak'gik and his worship.[Defiance/9] Hash'ak'gik was a pseudonym forcibly used by Turel, his vampire brother from the events of Soul Reaver: Azimuth, a devout worshipper of the Hylden, had summoned Turel back through time using a time-streaming device stolen from Moebius.[Defiance/9] The Hylden were an ancient race whose banishment in the Demon Realm was sustained by the Pillars of Nosgoth; they and the Unspoken were one and the same, and they were capable of possessing creatures in the Material Realm to do their bidding.[Defiance/11]
The entity behind Hash'ak'gik and the possession of Mortanius was the Hylden Lord, a leader among the banished militants. Turel, in his devolved state, was trapped, and utilized as the mouthpiece for the Hash'ak'gik cult; periodically possessed by various Hylden, he was used to command the cenobites of Avernus, thus facilitating the downfall of the Pillars, which would eventually give rise to Kain's empire. The words in the tome which Kain had discovered implied that it was all a cyclic phenomenon; Turel had taken part in Raziel's execution under Kain's command, and his order to his disciples that they "shed their [first born's] Blood on the altar of the world" to sustain him appeared to emulate the fate which would befall his brother in the distant future.[Defiance/9][Soul Reaver/1]
- The correct usage of the term "Hask'ak'gik" is notably kept somewhat vague throughout the series. It is initially implied (but never categorically stated) that the Dark Entity confronted at the end of the Blood Omen is the demon "Hash'ak'gik" with it also taking on the image from the floor of Hash'ak'gik's altar. Later titles however cast doubt on this: showing that the Hash'ak'gik cult actively worshipped the Possessed Turel as "Hash'ak'gik"; showing a different explanation for the transformation of flesh seen at the climax of Blood Omen; showing the Dark Entity was a Hylden (the same individual as the "Sarafan Lord" from Blood Omen 2) and addressing him specifically as "Hylden Lord" not "Hash'ak'gik". The Defiance design team addressed the complication as follows:
- ""Hash'ak'gik" is the name the human worshippers use for their god. The actual Hash entity is a leader among the Hylden, who has his own agenda. In Defiance, he possesses Janos. In Blood Omen, he uses the transformed body of Mortanius as a vessel. In Blood Omen 2, he appears as the Hylden Lord (AKA Sarafan Lord). When Raziel meets Turel, Turel is actually being possessed by a number of other Hylden (not the Hylden Lord). Many different Hylden did so in order to command their disciples."
- ―Amy Hennig
Within the story, only Turel is addressed as "Hash'ak'gik" and it is ultimately unclear whether "Hash'ak'gik" is the actual name of the Hylden Lord, a story created by the Hylden to inspire worship, or an actual myth or legend adapted and co-opted by the Hylden.
- The origin of "Hash'ak'gik" and the Hash'ak'gik cult is similarly kept vague with it suggested that the cult was present in Nosgoth "ages" before the events of Blood Omen. It was suggested by developers that Azimuth and Mortanius unearthed 'something' beneath Avernus that led to the formation of the cult though what exactly this was was never specified. It was also mentioned that Azimuth had used the Time streaming device she had possessed in Blood Omen to summon Turel from the far future of the events of Soul Reaver (or beyond) - therefore she at least was aware that Turel was simply a mouthpiece for the true leadership of the 'cult.
- Before Crystal Dynamics obtained the Legacy of Kain intellectual property, Silicon Knights had different plans for what they described as the "Blood Omen series". Although these plans would not come to fruition, their next game, 2002's Eternal Darkness: Sanity's Requiem, focused very heavily upon a grimoire dedicated to a dark god and found in a secret room - the Tome of Eternal Darkness. It seems possible that Hash'ak'gik's altar was originally intended to serve as a "teaser" for a potential sequel to Blood Omen: Legacy of Kain, and that this concept was absorbed into Eternal Darkness: Sanity's Requiem when Silicon Knights lost control of the Legacy of Kain IP.
- It is unclear whether the tome on Hash'ak'gik's altar was supposed to relate to the Dark Scripture in Legacy of Kain: Defiance. The maroon, leathery covers of the tome and the Scripture greatly resemble each other, but they were discovered in what seemed to be very different areas of the Cathedral.[Blood Omen/8][Defiance/9]
- Legacy of Kain Secrets: Page 9 of 9 at SK: The Complete Guide To Legacy of Kain (archived at Dark Chronicle)
- Question and Answer with Amy Hennig at The Lost Worlds (by Ben Lincoln)
- Answers to questions from the Defiance team at the Eidos forums (by Chris@Crystal)
- Hash'ak'gik and Hash'ak'gik's Altar at Dark Chronicle (by Ardeth Silvereni)
- Recreated PSXnation.com Interview with Denis Dyack at Nosgothic Realm
- Silicon Knights. Eternal Darkness: Sanity's Requiem. (Nintendo). Nintendo GameCube. (June 23, 2002)
- GLoK Interviews with Amy Hennig at Nosgothic Realm (by Raziel Fan)