I defeated him a few hours ago.

All of the characters were about lvl 32 except for Schera(lvl 34).

Here is how I did, you won't be receiving any damage this way.

The preparation:

Have Estelle equipped with Attack 3(there's no need for any Defense quartz, except to Schera, as you won't be receiving any damage here). If you have any or both of the Gladiator accessories, equip both on Estelle(I left both with Zane, shame me). All the girls must have Cast 2 quartz. Make sure to boost Schera's Speed to the max you can using quartz before going to battle, Action 3 is really welcome. Let Schera have one Defense 3 quartz so she can cast Earth Wall, and Mind 3 so she will have more magic power and Blue Impact(you can try another offensive Art here). Kloe will have Clock Up EX already, as she will be equipped with Cast 2 quartz. Make sure to equip a good offensive Art with Estelle, I've used Plasma Wave(again, explore your options here). Make sure to work your party battle formation as dispersed but yet inside a S radius, so S range Crafts/Arts will be fully functional. Make sure all of your characters are with full CP. There's a rare chance that the enemy will start the battle concentrating to use Anti-Sept All, so maybe you'll want to equip your characters with Glam Choker to prevent Mute, just in case the enemy uses Anti-Sept All before you can do something about it.

In battle:

In most of the times, the enemy will start the battle going straight forward and stop a few squares from your characters. In my game, I always start this battle with Schera as the fastest of my allies, or both Schera and Estelle. If you start with Estelle, make she use Morale. Schera, use Earth Wall with all of your characters in range(if Schera's speed is high enough, most of the times she will use it before the enemy attack you). Just note that Earth Wall/Earth Guard blocks Anti-Sept All from muting you(so if you didn't equipped your characters with Glam Choker, you're safe), but then your Guard is off just like a physical attack/Art does. With Kloe, use Clock Up EX on Schera just to make sure Schera will always use Earth Wall first than the enemy, and repeat it whenever you think Schera's Speed boost is about to debuff. If Kloe is free, always make her use Kaempfer on the enemy. Whenever Schera is able to attack, use offensive Arts on the enemy(I preferred Blue Impact). If any of your characters' Guard buff is already gone, use Earth Wall in your allies, or Earth Guard if only one of them is debuffed. With Estelle, I preferred using offensive Arts than physical attacks as I didn't got any ultimate weapons in this playthrough(I missed two Carnelia books), but if you have high attack with her, try what you think it's better to you. Keep doing this until the enemy HP is around 2.5k or 3k(depends on your physical power), and finish him with both Estelle and Schera's S-Crafts as Interrupt(preferably with Estelle over 200 CP and be sure that the enemy have his DEF DOWN and your allies STR UP).

You defeated him without taking any damage :D

I can't remember how many turns it took to defeat him, but it was kinda fast. Around 5~7 turns I believe. I left good quartz and accessories with Joshua's group(plus I missed both ultimate weapons), thus there are lots of room to improve here so you can defeat him even more easily. You can probably try to make Kloe to play the role of Schera using Earth Wall/Earth Guard Art, you're free to try. Just keep in mind that Kloe's Kaempfer Craft's STR & DEF debuff doesn't stand for very long so you'll need to use it very often.

I hope it may help you.

Best Regards.