Dragon Quest IX's grottoes have a strange difficulty curve. In one found through following a map called "Rock Mine of Doubt Lv.29," the monsters you encounter change thrice.
At first they're throwbacks to the early part of the game, then they're the sort that give about 300 experience points each (whereas monsters in the Realm of the Mighty give about 1750 per group per battle), then the boss is a machine with two attacks per turn.
Attacks that do damage ranging from 50 to 120 HP.
When party members have about 200 HP a piece a one-two punch from this boss just leaves them reeling. If my healer has a miss timed turn, one character - or the whole party - could wind up dead. Balancing on a pin like that makes for a tricky fight.
At least there are some Metal Medleys lurking in this grotto. So level grinding isn't impossible, just drawn out.
Writing of balancing on pins, though, I think that my party could get through the fight with Corvus at this point. And, not that it isn't fun, wrapping this game up sooner rather than later is definitely something I'm keen on doing.