Legacy of Kain: Soul Reaver

... Although you were no longer a vampire, you still suffered some of their natural weaknesses, such that of water burning you like acid or sun scorching your skin like fire. However, you rid most of these weaknesses from yourself over time as you devour the souls of your slain enemies. You're young in your new form, though, and can't hold your physical form forever in the material realm, constantly draining your strength, the longer you stay there unsated. So at any time you're weakened too much, you're transported back into the spirit realm where you can sate your hunger with the lost souls. Your ability to transport yourself back and forth between material and spiritual realms is fundamental to your success, and adds an interesting depth to some puzzles and fights. However, you're practically immortal, even if you were to die, as if you could, you're transported back to the underworld, below throbbing tendrils and the everwatchful gaze of the Elder.