Era
Dark Ages
You can enter the Black Omen from the Dark Ages, the Middle Ages, or the Present, but it exists outside of time so it makes no difference. Clearing the Black Omen in any Era will remove it from all Eras, and you can't collect any Treasures twice regardless of which Era you collect them in.
This is the longest dungeon in the game, complete with seven (!) Boss fights, and some fantastic Treasure. There are some nasty Monsters in here, but you can Charm great items from many of them. Finishing the Black Omen will leave the party well-prepared for Lavos. That said, you don't actually have to enter the Black Omen at all—it is strictly optional.
The first room contains the first Boss, the first of three Mutant Bosses. The Mega Mutant inflicts various status ailments. Defeat the Upper Part first, and Charm a Vigil Hat from the Bottom Part if you're so inclined.
Eventually you'll run into Boss Orbs, which are another version of the Rubble/Turret enemies you've seen before. The Boss Orb is basically a normal enemy, and you should kill it first. The Side Kicks are hard to hit but give generous TP rewards. If you haven't learned every Tech with every Character yet, it's relatively easy to do so in the Black Omen.
After some time you'll find a save point and a pair of Nus. One will allow you to exit the Black Omen, and the other will sell some nice potions.
A long while later, you'll run into the Giga Mutant. You can Charm nice rings from both parts of this Boss. The Giga Mutant is virtually immune to Physical attacks, so use magic and elemental Techs to fight it. It will counterattack magic by draining MP, so you'll likely be low after the fight. If so, use a Shelter at the save point before the Boss.
Once you hit another save point, it's time for the TerraMutant. Once again, there are nice Accessories to Charm away. Use elemental Techs and magic on the Upper Part, and ignore the Bottom Part entirely.
After that, you'll fight a Lavos Spawn more powerful than those on Death Peak. You can steal a Haste Helm from the Mouth and a Safe Helm from the Shell (which is worth the counterattack).
One last save point leads to the final Boss fights, three in a row featuring Queen Zeal and the Mammon Machine. Queen Zeal's first form likes to drop everyone to dangerously low HP. Frog Squash and Dino Tail are very effective as a result.
Next up is the Mammon Machine. It doesn't attack normally, so just beat on it and heal the party from the fight with Queen Zeal. Physical attacks quickly become useless, while magic powers up its eventual counterattack.
Finally, you'll take on Queen Zeal's face, along with two Arms. The Arms have nasty counterattacks, so don't use Techs that hit everyone (including Dino Tail and Frog Squash). You can Charm some nice Armor from the Arms, however. Don't hesitate to use MegaElixirs if you need them.
Finishing off these Bosses isn't quite the end, though... it's time for all twelve of Lavos's forms! (Yes, really.) Actually, you can stop after 10 if you want. Check out the "Day of Lavos" Area for more information on Lavos.
This is the longest dungeon in the game, complete with seven (!) Boss fights, and some fantastic Treasure. There are some nasty Monsters in here, but you can Charm great items from many of them. Finishing the Black Omen will leave the party well-prepared for Lavos. That said, you don't actually have to enter the Black Omen at all—it is strictly optional.
The first room contains the first Boss, the first of three Mutant Bosses. The Mega Mutant inflicts various status ailments. Defeat the Upper Part first, and Charm a Vigil Hat from the Bottom Part if you're so inclined.
Eventually you'll run into Boss Orbs, which are another version of the Rubble/Turret enemies you've seen before. The Boss Orb is basically a normal enemy, and you should kill it first. The Side Kicks are hard to hit but give generous TP rewards. If you haven't learned every Tech with every Character yet, it's relatively easy to do so in the Black Omen.
After some time you'll find a save point and a pair of Nus. One will allow you to exit the Black Omen, and the other will sell some nice potions.
A long while later, you'll run into the Giga Mutant. You can Charm nice rings from both parts of this Boss. The Giga Mutant is virtually immune to Physical attacks, so use magic and elemental Techs to fight it. It will counterattack magic by draining MP, so you'll likely be low after the fight. If so, use a Shelter at the save point before the Boss.
Once you hit another save point, it's time for the TerraMutant. Once again, there are nice Accessories to Charm away. Use elemental Techs and magic on the Upper Part, and ignore the Bottom Part entirely.
After that, you'll fight a Lavos Spawn more powerful than those on Death Peak. You can steal a Haste Helm from the Mouth and a Safe Helm from the Shell (which is worth the counterattack).
One last save point leads to the final Boss fights, three in a row featuring Queen Zeal and the Mammon Machine. Queen Zeal's first form likes to drop everyone to dangerously low HP. Frog Squash and Dino Tail are very effective as a result.
Next up is the Mammon Machine. It doesn't attack normally, so just beat on it and heal the party from the fight with Queen Zeal. Physical attacks quickly become useless, while magic powers up its eventual counterattack.
Finally, you'll take on Queen Zeal's face, along with two Arms. The Arms have nasty counterattacks, so don't use Techs that hit everyone (including Dino Tail and Frog Squash). You can Charm some nice Armor from the Arms, however. Don't hesitate to use MegaElixirs if you need them.
Finishing off these Bosses isn't quite the end, though... it's time for all twelve of Lavos's forms! (Yes, really.) Actually, you can stop after 10 if you want. Check out the "Day of Lavos" Area for more information on Lavos.