The Kain Reaver, also known as the Amplified Reaver was an enhancement for the Wraith Blade that was planned for inclusion in Legacy of Kain: Soul Reaver, but was ultimately cut due to time constraints.
The Kain Reaver was an enhancement for the Wraith blade that Raziel was intended to gain when he visited Kain's Mountain Retreat and struck him down with the Ariel Reaver. Absorbing Kain's soul, the Reaver would have become an all powerful super weapon which would enable him to fight off the vampire hoard at the Pinnacle of the Silenced Cathedral. Like the Ariel Reaver, it was a permanent enhancement which replaced and encompassed the abilities of all of his other Reavers.
Despite being removed, the blade can be activated in game through the use of the debug menu, revealing it had a black core (white in PC versions of the game) enshrouded by red energies. None of its abilities were present in-game.[Soul Reaver]
In the June 1st Beta the Ariel Reaver is not strictly present in the Chronoplast visions instead a red and black Reaver - matching the colorscheme of the Kain Reaver is gained from Ariel's death - potentially suggesting this may have been the original colorscheme intended for the overarching Amplified Reaver and that the Ariel Reaver was added later. Artist Daniel Cabuco said of the colors:
The exact relationship between the Amplified Reaver, Ariel Reaver and Kain Reaver was something of a mystery until alpha builds of Soul Reaver were publicized in 2020. The Amplified Reaver was known to exist and was mentioned in prerelease interviews and materials as an all-powerful blade superseding and encompassing the prior elements. But the retail game made no mention of this - instead referring to the two blades seen in the Chronoplast Visions as the Ariel Reaver and the Kain Reaver. In the retail version of Legacy of Kain: Soul Reaver Debug menus can be used to activate various version of the Wraith Blade - among them are variants named the Ariel Reaver and the Kain Reaver - presumably reflecting the permanent alterations gained by Reaver consuming the souls of Ariel and Kain respectively - each with its own design.
The alpha revealed that neither Ariel or Kain Reaver had been present originally and instead the Reaver list was purely made up of the 'elemental' Reaver enhancements. The Amplified Soul Reaver was listed differently as an ability - the last in the game - although activating it didn't appear to have any effect at this time. As the game moved into beta development most of the famous cut content was removed including the Amplified Reaver, but some time later the Chronoplast Visions were recorded and during this time the Sunlight and Spirit Reavers were repurposed - and in some case recolored - to become the Ariel and Kain Reavers, respectively. These stood in for the Amplified Reaver in the visions and were left into the retail game, resulting in not just the absence of the Amplified Reaver but the Sunlight and Spirit Reavers as well.
- The Kain Reaver does make an appearance in-game: it is the blade Raziel is seen holding in the last Chronoplast Vision (with the balcony). This scene would later be performed in canon at the end of Soul Reaver 2, with the Fire Reaver stepping in for the Amplified Reaver.[Soul Reaver/15][Soul Reaver 2/9]
- The concept of an all powerful super weapon used at the end of the game has reappeared in future games; Soul Reaver 2 not only had the 'Blood' Reaver but originally had another super weapon, the Spirit Reaver (modified from it Original Soul Reaver elemental properties.) This would be modified further in Defiance, with Raziel finally gaining the Spirit Reaver and Kain gaining the Soul Reaver, although only the Spirit Reaver has its all powerful properties in game[Soul Reaver 2][Defiance].