In the distant past, the Great Condemner, too, sought such power, and was stricken down by the gods. Even now, his spirit is bound within the Stilshrine of Miriam. Know the fate of those who have fallen in their search for strength.
Honoring the law more than any other, a scion of holy order and condemner of criminals. Created in opposition to Knight-Star Pashtarot, scion of light. He turns his deep, abiding hatred for those who break the law into living darkness, therein to plunge the guilty in fell judgment. Over time, he came to care less for upholding the law and more for condemnation, and so tainted by hate, he sought to condemn the gods themselves to death. Thus, did he earn the title "The Condemner", and thus did he fall from grace.
This can be a difficult battle. During the battle the Magicks command is sealed. Zeromus is flanked by eight to ten Dark Lords. Zeromus casts Piercing Graviga, which can easily defeat characters, and uses a number of time spells: Slow and Stop on the party, and Hastega on himself and the Dark Lords. Zeromus has high HP and uses Great Barrier when he drops to 50% health.
It is probably best not to attempt this Esper until after the Giruvegan plot event, to access better armor, weaponry, and items. Since magick is sealed items will be important, including X-Potions; Power Armlet and Bubble Belt accessories and items that protect against Slow are useful.
It is essential to cast buffs upon the party before the battle, but casting Bubble is not encouraged since this will increase Zeromus's Piercing Gravija damage (however, constant Bubble status through the Bubble Belt is alright). Reflect is a useful status here, protecting against Zeromus's Slow and Stop spells.
The Pheasant Netsuke makes healing items more powerful and combined with all the Phoenix Down augments, a Phoenix Down can recover a KO'd character back to full health. Revive-item gambits are essential because Piercing Graviga will often defeat characters. Because as many as 20–30 Dark Lords can spawn in this area, finishing the battle quickly is important.
If the party uses many Quickenings at the start of the battle, Zeromus can be defeated rapidly at a relatively low level. If all characters have Mist Charges, four Quickening chains can be used at the start of the battle by swapping characters out; MP-restoring items allow more chains to be initiated. The player can set the battle speed all the way down to maximize a Quickening strategy, as items and Quickenings have no Charge Time, but it slows the Dark Lords and Zeromus.