reichtfeld said:If you can dictate terms for the match then no flying and no spells. And pretty much the only way to do that would be playing off the devil's pride. They are lawful creatures after all and might abide by such an agreement unless threatened with death. Something along the lines of "What need would such a mighty lord of darkness such as yourself have for those tactics against one as lowly as I? Enjoy the satisfaction of rending my mortal flesh with claws and crushing my puny frame with your tail. There is no need to take to the sky when you can relish swift victory on the ground. Your mighty magics would be a waste against me."
In a stand-up melee fight your main objective would be pushing your Fortitude save through the roof against that poison. I'd also suggest using Expertise and staying mobile to avoid a full attack, since that means you'd avoid the bite/poison altogether as well as the chance at getting grappled by the tail.
Eh. The poison is easy-peasy. It's a DC 21 Fort save to negate, which means he only needs a 4 as it is. Add an endurance spell, and it gets even easier.
No, the one to watch out for is the fear aura, which is a DC 19 Will save. With a mere +9 Will, that's a significant chance of being turned into a quivering lump of jelly in the first round.
Assuming he can deal with this, the best tactic is to close in ASAP, and try to get off a full attack on the thing. Hasted,
he gets 4 attacks per round, with the last one a 50-50 chance to beat the pit fiend's AC of 30. If he can keep the fiend from running away, two rounds of this and it's toast. (Get the party cleric to cast magic weapon on the sword beforehand, so that it's blessed and negates the fiend's DR -- although personally I'd treat a sun blade as blessed already.)