Boss Battle: Shrieker

As seems to have become standard in the first two Final Fantasies, reaching the Shrieker is more difficult than defeating him. Before leaving for Kas'ion I recommend picking up another Cure scroll. You'll see why. You'll also need 400 gil to pay Cid for an airship ride down to the castle.

Seconds after you enter Kas'ion you'll meet Gordon skulking the shadows of a stairwell. He came to retrieve the Sunfire but couldn't handle the castle's baddies. (Weenie). He's more than happy to join you, though, and you should feel free to use that extra Cure scroll to add another healer to your party. :)

Soldier on until you reach the Shrieker.

Your first few turns agains the Shrieker may cause you some anxiety. He absorbs all spells cast at him (and I mean all; he will gain life if you try to cast sleep, for instance, not just from damage spells) and he casts medium level versions of fire, ice, and bolt that will do a decent amount of damage to your entire group. Fortunately his shriek is more dangerous than his bite. Cast cure on your party members as often as necessary to survive the first five to six turns and the Shrieker will run out of mana. Reduced to meager physical attacks it becomes a game of endurance, and you have four to one odds. Wail away at him, trying as best as able to ignore the meager amounts of damage you're doing per hit, and eventually he will die. It might take five or six minutes, just fyi.

Boss Battle - Adamantoise

Technically the first boss that you'll face in FF2 is the Sergeant that confronts you in the Semite Falls Mines, but much like your encounter with Garland at the beginning of FF1 the Sergeant is really just an idiot proof test. If you can find the attack button you can defeat him, especially with Mindu in your party offering you the full range of white magic. Adamantoise, the snapper turtle with a Wolverine-esque shell awaits you at the end of your quest for the Goddess Bell, however, and the unwary adventurer could easily lose a finger or two to his snapping maw.

You may have noticed that when Mindu first joined your party he brought with him a valueable ether. The savy player will have taken said either away from Mindu before he has a chance to leave your group, and if you've arrived at the battle agains the Adamantoise without any remaining MP that ether may be your life saver, as the hungry turtle takes virtually 0 physical damage. He also hits like a two ton truck, and needs to go down fast if you want all of your warriors to survive the fight. Fortunately he's extremely vulnerable to ice, so open up with a few spells and he should go belly up, and everyone knows turtes can't roll over.