The most dangerous enemies in Etrian Odyssey III hunt you down. Formido Oppugnatura Exsequens or F.O.E.s appear on the all-important map so you can avoid them. F.O.E.s have some advantages over the player like moving even while you’re occupied with other monsters. Take too long and they’ll join the fight.
Here’s a look at some of the F.O.E.s in Etrian Odyssey III. Hopefully, you’ll see them in the game when you’re strong enough to slay them.