The Tavern

http://pastebin.com/mUPLVkKL

I just got a 3-rune victory with my latest MiBe. I feel like the game just clicked with me this run. I made sure to be very cautious all run long, trying to lead monsters around corners so I wouldn't have to run into the fog of war, and taking extra precautions if I even had a tiny bit of doubt that a particular mob would be difficult. I think that went a long way.

I did get a bit lucky with my resistance gear, I think. The two closest calls I had were on Zot 4 and on my ascension run, where I ran into a Curse Toe and a Tormentor, respectively. Makes me wonder how people do 15-rune runs, with all that torment going on.

I'm thinking of doing a caster next, any advice on that front? I've never even made it to a single rune on a caster.

First, congrats.

Second, a caster:
For background, I think conjurer is the best. Train only conjurations, learn battlesphere at XL5, train charms to get it online. After that, train whatever you want.
For species: I recommend Gr, Te or Dr.

Well done!

Congratulations on you first win! I actually had the exact same question about casters a couple of days ago (also after having my first win as a MiBe).
I've treid a couple of backgrounds and I would recommend a wizard. The thing about wizards is that they don't have a lot of nuking power but are very versatile. As a MiBe you usually solve problems just with berserk or BiA, basically just punching things until they die. With a wizard you can't do that, so instead you have to use Mephitic, blink or imps depending on the situation. I think it can help you learn casters and get rid of all the bad habits you get after playing MiBe for a while. Also, since you are not specializing in any magic school, you can pretty much use any book the dungeon gives you.
As for races, I like playing Spriggans and Deep Elves. But if you want something a little harder to kill you could go with Draconians.

Undead species, Kiku worshippers, TSO worshippers all have an edge here.

Additionally, rNegative pips reduce the damage done by torment by 5% (which is why TSO worshippers have an edge). This stacks with Kiku's innate torment "resistance".

(Demonspawn can also get a mutation that mitigates torment as well, but I wouldn't count on getting it.)

I've only won one 15-rune game (out of two total wins) by playing a caster. It's pretty easy to avoid torment when you can destroy everything in sight in 1-3 turns. It's getting him to that point that is the difficulty.

Also you can use high Stealth, Makhleb, Statue Form, Necromutation, cloak of Fog, Controlled Blink.

Makhleb? How so?