This hasn't been revealed yet.
The SR1 era vampires (and Kain himself) are the only ones to have their method of creation explained, and this is apparently quite different to the earlier vampire generations
The first Legacy Of Kain Game is Blood Omen: Legacy of Kain
Legacy of Kain was created in 1996.
Raziel - Legacy of Kain - was created in 1999.
So far Eidos or Crystal Dynamics have not announced an official Legacy of Kain game however a fan-made game is available to Download. It is called Legacy of Kain: Prodigal Sons
There are currently five: - Blood Omen: Legacy of Kain (1996) Legacy of Kain: Soul Reaver (1999) Soul Reaver 2 (2001) Blood Omen 2 (2002) Legacy of Kain: Defiance (2003) A sixth game - Legacy of Kain: The Dark Prophecy - was cancelled in 2004 and (as of 2012) there has been no official word on any series continuation, besides a few insubstantial rumors.
Blood Omen Legacy of Kain - 1996 VG is rated/received certificates of: USA:M
No
Blood Omen Legacy of Kain - 1996 VG was released on: USA: 5 April 1996
Legacy of Kain: Defiance
Blood Omen II Legacy of Kain - 2002 VG was released on: USA: 2 February 2002
no, there was rumour on the net that Uwe Boll would be making one based on a Wikipedia entry, however, that entry has been removed and no such knowledge of a Legacy of Kain Movie exists
It's available on PSN or GOG now