The areas west of Palamecia desert, where you are likely to land your ship if you head to the Coliseum by sea, are home exclusively to high-HP Monsters. The new Antlions can Paralyze your party members and deal a lot of damage, but they're vulnerable to both Ice and Poison. The Land Rays also Paralyze with their attacks, but have no weaknesses. At this point in the game, Cottages should be quite affordable, so go all-out against these foes and rest up at your destination.