There is a fairly obvious passage leading west from the southwestern island. Beware, though, because all four chests in the hidden area have guardians. The Peryton is basically just another enemy with a nasty attack. The Zombie Dragon has a ton of HP but doesn't really have any tricks, and has the usual undead weaknesses to Fire and Cure Spells. The Eater is only tough if it starts using Divide. The Death Claw is especially interesting since any physical attack that doesn't kill it will cause it to Divide automatically. Either use Spells against it, or combine abilities (such as Haste, Cheer, Boost, or Jump) to kill it in one attack.