@William & Tinker: Thanks!
Anyway, I dived in and took my first test run as a Rat. Found that I wasted a lot of blackspace and couldn't even clear the first floor. Problem was I was finding it hard to maintain my piety, I had to make sure I had 10 or more before I level up and each new monster hit also took away 4. Pisorfing mobs to the edge of the top level only gives 5 piety. I saw for Eastless' attempt, he took the free 50 piety from PM (I didn't, and Tinker did not too for her 2 successful attempts). Understand that it may limit how far you can take Sanguine to later (15% is still quite decent), so Tinker, what is your advice on this?
@DarkDungeoneer1020: Cool, nice win!
Is Dragon Isles the only Vicious Dungeon you have attempted? You should definitely try to unlock Vampire by clearing Vicious Steel first, should be the "easiest" of the Vicious Dungeons.
Namtar's Lair and Demonic Library are roughly the same in difficulty (thereabouts), and Naga City should be the hardest. Needless to say, VGT will be for last.
You can probably try them out first and let us know if you need recommended builds or strategies,