I haven\'t played the original Dissidia\'s story since I first picked it up years ago. But fighting him for sh*ts and giggles in Duodecim, he still reminds me that he can still kick my a** if I don\'t put in the effort.
My best advice is to have the best possible equipment and summons available to you. It\'s all about stamina with Chaos, if you have less than 50% health the third round, you may as well count it as a loss and hit the showers.
Each round he gets more aggressive, so round one, put the pressure on him. Even if he breaks you, keep on him, in my experience, he doesn\'t use too many HP attacks first round.
Second round is all about finding that synergy between offense and defense, cause he starts cranking out HP attacks. Keep attacking, but keep an eye out for the attack he uses that generates a wall of flame around himself and pulls you in.
Third round, he\'s trying to tear you a new one. Keep a cool head and be ready to stay on the defensive. Since it can be hard to tell if he\'s using a bravery or HP attack, you\'re going to have to learn his moves. Never attack him until you\'ve either blocked his attack, which is a bit hard to do, or the second you successfully dodge.
The best trick I can tell you is use the Magic Jar Summon. Since it\'s so easy for him to break you and build up his bravery round one, you can use that against him. Once he has a nice chunk, use a HP attack on him and use your summon once your HP attack connects. I know it\'s seems like an obvious tactic, but if you use it too early, you risk him chipping away at what you copy from him. But keep in mind, whenever you use the summon, you won\'t be able to use it for the rest of the battle, so time it\'s use wisely.
Hope that helps.
If I remember correctly Random, you don\'t get to play as the villains in the story mode. Maybe Freelance can confirm it for you.