How do you defeat Barthandelus in Final Fantasy XIII?

Answer 1

The easiest way to beat a dreadnought, is to inflict status ailments, like deshell, deprotect, etc. It will then use a timeconsuming ability to get rid of the ailments. While he's doing this you can attack him get him staggered.

Answer 2

How I defeated him was:

Battle Team: Lightning/Fang/Hope

Main Paradigms: Commando/Sentinel/Medic, Commando/Commando/Medic, Ravager/ Commando/ Ravager.

First you take out the ugly pale faces, two at a time with Lightning as a Commando using Blitz. Have Fang be Sentinel and hope be a Medic.

Once you take out all four pale faces, summon Odin.

Then you shift between paradigms. When HP is low, have hope be a Medic. If HP is REALLY low, have Hope be a Medic and Fang be a Sentinel.

Hopefully Barthandelus doesn't doom you, but if he does, fight for your life!

GOOD LUCK!