3, 2, 1.../Strategies

Melee and Black Mage strategy

A recommended strategy would involve two melee capable of performing a fusion skillchain and four Black Mages.

Take note that although logically they should be resistant to Fire elemental damage, they are in fact weak to Fire.

Upon entering, have the Black Mages open the fight with a timed Elemental Seal Freeze. As soon as the spells connect, have the two melee begin to attack while the Black Mages spam their best spells. When the melees have enough TP, perform a Fusion skillchain and have the Black Mages magic burst with Fire II. This strategy works best if the two melee are Samurai, because they can Meditate upon entering the BCNM (and then because of the 30 minute time limit of the battlefield itself, you can afford to wait and allow the Meditate recast timer to reset), as well as use their Meikyo Shisui.

Melee and Red Mage strategy

This strategy is similar to the previously mentioned strategy, except that it requires around four Red Mages with their Chainspell ability ready.

Upon entering the BCNM, have the Red Mages activate their two hours and begin spamming Fire II while the melee attack and perform Fusion skillchains as often as possible. Because the Red Mages are using Fire II as quickly as possible, timing for magic bursting off the skillchains won't be necessary. Once the Red Mages run out of mp, simply Convert to restore mp and continue on.