Kefka unleashed many evils when he undid the world, and among them are the Eight Dragons. Appearing only in the World of Ruin, and therefore in the second half of the game, the Eight Dragons serve as optional bosses that populate various dungeons. Unlike other enemies they appear on the map, occasionally moving freely as NPCs, and as soon as you approach one you’ll engage in combat. Each Dragon reflects one of the eight elemental properties of Final Fantasy VI, and known that property will help you face the Dragons. Defeat all Eight Dragons, and… well, you’ll see.
Found wandering the snow fields beyond Narshe, just before you find the Frozen Esper. The Ice Dragon lives up to its name, not only using high-level ice spells but attacks that can freeze your team members in their tracks. It also likes to counter physical attacks with its own strike, one of fairly moderate power. The Ice Dragon is, predictably, vulnerable to fire spells, so bust out Fira / Firaga or any fiery weapons you have to beat it down. Use Fire on your team if anybody gets frozen to effect a thaw and get them back into the fight. You’ll find a Force Shield after defeating the Ice Dragon.
Found in the Opera House, sitting on the stage. You need to pull the right switch in the cluster of three switches in the right backstage room to fall down to the stage. The Earth Dragon specializes in, whaddya know, earth-elemental attacks, and loves to attack you with Quake in particular. Cast Float or give your team members before you begin the battle to negate its elemental advantage, then rip it apart with wind or water attacks. The Earth Dragon has some very strong physical attacks, so Vanish is not out of the question. The Earth Dragon will occasionally pull you back to the ground with 50 Gs if you’re not wearing Angel Wings, so make sure you reapply Float in a hurry. Not that bad a fight so long as you prevent it from landing too many of its punishing physical attacks. You’ll gain a Magus Rod for defeating the Earth Dragon.
Found in the Phoenix Cave, not far from the end of the Cave. The Red Dragon, surprise surprise, is a fire-based creature that relies on fire magic. Early in the fight it will use Fira; as you do more damage it will switch to Firaga and Flare. Predictable, if quite painful without fire protection. The Red Dragon will also counter virtually every attack with a physical swipe of its own. The battle goes pretty much as you’d expect: use strong physical attacks and anything with ice attached, particularly the Blizzard family of spells. Not too difficult overall. You’ll gain a Murakumo for defeating the Red Dragon.
Found in the Ancient Castle, in the secret room where you morph the Odin magicite into Raiden. The Blue Dragon is an almost strictly offensive boss that relies on water attacks, and it will attempt to wash your characters away with a series of all-hitting strikes. Keep yourself healed and maul the thing with lightning magic, by far its greatest weakness. Despite the Blue Dragon’s high HP it won’t take many hits from Thundara, Thundaga, or lightning-elemental weapons to bring it down. Beating the Blue Dragon will earn you the Zantetsuken.
Found in the third treasure room of the Cultist’s Tower. Despite the difficulty of getting up here, as well as your inability to use anything but magic, the Holy Dragon is a piece of cake. It doesn’t have much HP, its only real attack is Holy - which it uses over and over - and you can waste virtually all of its turns if you have Reflect Rings equipped, which it will attempt to dispel with no success. So long as you have some moderately-powerful attack magic at your command this is a pretty simple fight. You’ll gain a Holy Lance for defeating the Holy Dragon.
Found in Mt. Zozo by hitting a switch, opening a chest, and waiting for it to run into you. The Storm Dragon is one of the most difficult of the Eight Dragons. Not only does it have a very painful physical attack, it likes to use Cyclonic, an attack that can reduce everyone to low HP levels, and several all-hitting attacks which could wipe your party out if you’re very unlucky. One person should always always always be ready to heal while the others go after Storm Dragon with lightning-elemental attacks. This bruiser likes to counterattack a lot, so don’t waste piddly normal attacks on the Storm Dragon unless you know they’re going to inflict a lot of damage. You’ll gain Force Armor for defeating the Storm Dragon.
Found down the middle path in Kefka’s Tower. Another relatively easy Eight Dragons fight. The Gold Dragon is a lightning-elemental creature, and its attacks almost universally reflect its nature. At its strongest the Gold Dragon will use Gigavolt to hit one or all of your characters for an admittedly painful amount of damage, but by this point it shouldn’t be enough to one-hit anybody. The Gold Dragon is specifically weak to water, but you can simply rely on special attacks that aren’t lightning-elemental to bring it down. No big deal. You’ll gain the Crystal Orb for beating the Gold Dragon.
Found down the right path in Kefka’s Tower. The Skull Dragon is another relatively evil fight so long as you have protection against status attacks, as it can hit you with doom status and confuse your characters. Otherwise it doesn’t do a whole lot of damage, and if you have even a single powerful fire attack you can smash this sucker. Firaga is easily your best and most economical weapon against the Skull Dragon if you’re at a lower level. Otherwise, holy- or fire-elemental attacks from weapons will get you through the fight rather speedily. You’ll receive a Muscle Belt for destroying the Skull Dragon.
Defeating all eight of the Eight Dragons will earn you the Crusader magicite, regardless of where you are when you kill the last one. In the later releases of Final Fantasy VI (GBA onward) you will also unlock the Dragons’ Den, an exclusive dungeon that serves as one of the most difficult areas in the game. You should only attempt the Dragons’ Den if you can beat the game, as the enemies here are… yikes.