[Fathom Zero]

You can unlock a ton of doors early on, which is pretty useful. I dunno how good the Thief is otherwise, though. I started as a Deprived because I wanted the flat stats to build anything on.

I think you can get the Pyromancy Flame from the start if you have the Skeleton Key. It's a good thing to have if you don't want to build a magic user because the power of the spells doesn't scale off of any stats, but rather how mnay times you've upgraded the flame with souls. And, as I said in my little thing above, the final boss practically necessitates it.