Invulnerability the easy way:

 1. Go into your Blood Omen 2 directory (i.e. D:\games\blood omen 2 .... etc)
 2. Get into Data folder and locate game.erg file. You can open it with notepad.
 3. Within game.erg locate the following line

    "-BO2 Kain Debug Flags\kain's invulnerable"=1

    All you got to do is to delete - so the line would read

    "BO2 Kain Debug Flags\kain's invulnerable"=1

 Save the file and start the game.