So far i've killed Satan twice successfully

Build 1: 

Searing -> Weapon Spec -> Heavy -> Faith -> Heal ->Heal-> Heal

Build 2: 

Searing-> Weapon Spec -> Heavy-> Faith -> Heal->Whack->Heal

So, with build one, it's your traditional slice and dice. Make sure you pick up plate and an axe, or a tower+12345 and preferredly a +5 sword. This will make bone demons easy. 

Important thing in Dungeon 4 levels is to overheal !!! This makes taking out the ghosts easier.

Also, Make sure you capitalize on the love and peace bugs, get more energy than health bugs though, as once you max out heal energy = life.

With build 2, you need to do the same, just use a wand instead. I added the whack, because that way you can stay in a corner, and toss energy potions and whack the monsters back, to give you two+ turns.

Good hunting!

I've been playing around with more of a magic oriented crusader lately.  He turns out to be quite viable, and I got down to Satan with him.  Focus on getting a wand and whatever armor you can grab and you're good to go.  He's actually quite fun to play, and adds another level to Crusader play.  I usually go something like this:

Whack -> Holy Fire -> Martyrin' -> Faith -> stack on whack/fire -or- heal -> etc.

You have to be smart how you play him, but with a little luck you can create a rogue that deals an insane amount of damage.  The problem with him is he takes an insane amount of damage if not played right.  You'll want to throw rocks/daggers and position yourself so that you are surrounded as much as possible.  Holy Fires is a skill that (in my opinion) is sorely underrated.