Curse of the Immortal

The discrepancy between the law of Nature that dictates all living things must die, and the immortality of the Old Gods.

God-Death

This affects all living things equally, as it is death itself. However, complications only arise for the immortal who cannot die.

Normal lifeforms will simply die of this disease, however immortals will gradually be stretched so thin over time that they become invisible, intangible, almost non existent, but not dead.

Eternity

The long lived Dwarves also suffered some of the stretching effects, however the fact they still had finite lives meant it didn't amount to very much more than dementia-like symptoms and mild invisibility.

God-Death existed before life itself, and the Old Gods were immediately afflicted upon entering into the world.