Help my party take out a Pit Fiend

[Endur]

Helpful Magic Items
Bane ability
Holy ability
Chaotic ability

Arrows of Slaying

Oathbow

Iron Jar

similar types of items

 

[Shemeska]

Scream "Tanar'ri!!!!" and point at someplace randomly behind him. About half the time you do this, have one of the wizards in your party have actually summoned a few Tanar'ri.

*chuckle*

Ask your friendly neighborhood highclass 'loth for advice and/or aid. Even if she doesn't do anything herself, as always, she'll know a guy who knows a guy who'll... etc

 

[dungeon blaster]

Actually, that's a good idea, planar ally a glabrezu or other powerful tanar'ri. It would likely agree, knowing that it has a chance to take out a powerful devil and can teleport away if the going gets too tough.