The Lake of the Dead
The Lake of the Dead featured in Blood Omen and Soul Reaver.
In Soul Reaver, Kain sentenced Raziel "to burn forever in the bowels of the Lake of the Dead". This implied that the Abyss was situated in the lake of that name, and that its waters fed the whirlpool.
The Lake of the Dead could be located on Maps of Nosgoth. The in-game map for Blood Omen showed it clearly. It did not contain the Abyss in that era; instead it had an island with a teleporter that took Kain to the Lost City. The lake could be explored by travelling west from the Mist Form dungeon and, unless he resorted to Bat Form, Kain crossed part of it to reach Vorador's Mansion.
Amy Hennig (Director and storywriter of Soul Reaver, Soul Reaver 2 and Defiance) has said there is a connection between the Lost City and the Abyss, but at the current time, there is no explaination as to what that link is, except that they appear to share the same location, both being in the Lake of the Dead.
- [SR1] Raziel: "I, Raziel, was to suffer the fate of traitors and weaklings - to burn forever in the bowels of the Lake of the Dead."
- Warp's answers from Amy at the Eidos Forums