User blog comment:Zelron/Soul of the Dragon (Why the soul gotta be black?)/@comment-30303790-20121002192452/@comment-3492791-20121003024752

As Valerica told us, spending time in the Soul Carin has "a little bit of you rub off on the Soul Carin, and a bit of it filled the void". If this prosess can occur over a few hours of being there, imagine the effect after a near millennia of being there.

The closest example of this I can think of might be Decompression Sickness.