In its later incarnations (GBA onward), Final Fantasy VI included several extra bonuses. Among them were four brand-new Espers, available upon unlocking the Falcon in the World of Ruin. The four Espers, and the magicite they yield, are all quite powerful and worth the time to unlock.

Final Fantasy VI copyright Square Enix.
Images used for educational purposes only.

Leviathan

The first of the extra Espers you’ll find, and possibly the easiest to obtain - though not necessarily easy. Leviathan appears to attack you if you attempt to take the ferry between Nikeah and South Figaro after obtaining the Falcon. 

In combat Leviathan is an all-hitting jerk, using El Nino and Tsunami to inflict mass amounts of damage on your team. If you have equipment that can block or absorb water, this is the battle to use it. Otherwise, put one person on Curaga duty while the others battle Leviathan with your strongest non-water attacks. Nothing special, just ravage it with brute force. 

(For the record, this battle’s the only place in the World of Ruin where Mog can learn his Water Harmony Dance, assuming you missed it in the World of Balance. Don’t waste this fight.)


Cactuar

To gain Cactuar you must defeat the Gigantuar, found in the desert near Maranda after you’ve defeated enough Cactuars (tenish). This epic beast only appears in the southwestern portion of the desert, amid Slag Worms and normal Cactuars, and is quite powerful. 

It will emulate normal Cactuars in using 1,000 Needles, but will also ratchet up the pain by using this attack multiple times. It can also crush your foes for a heap of damage. Gigantuar can only be hit by moves that cannot miss, meaning special attacks (Throw, Tools, Blitz) and spells such as Flare and Ultima. Nothing else will work. As Gigantuar dies it will use 1,000 Needles ten times on your party, moving from character to character, so you need at least 10,000 health - or a way to completely avoid the attack - to get through this fight. Someone should be healing your party at all times.


Gilgamesh

Gilgamesh is found at the Coliseum, but you need something else before you can lure him out to play. Head to Jidoor’s Auction House and you’ll see an auction for Excalipoor. Purchase it for 500,000 gil (ouch), then bet it at the Coliseum to fight an easy Onion Dasher for a Merit Award. Gilgamesh will attack in the aftermath. 

This isn’t an easy battle at low levels. Early in the fight Gilgamesh will couple constant counterattacks with a variety of powerful spells and several Lores for Strago, the most painful of which is easily Revenge Blast after a handful of hits. Do enough damage and, after boosting his stats, Gilgamesh will swap to a cycle of jumping, using a powerful normal attack called Blade Dance, and emulating Shadow’s Throw command to hit you with some really painful weapons. 9,999 damage is pretty common. You can alleviate a great deal of pain by Vanishing your party members for the second half of the fight, as Gilgamesh’s attacks will alllll miss against Vanished characters. Hit him with your best attacks thereafter and bring him down before Vanish can wear off. Along with the magicite you’ll gain Genji Armor for defeating Gilgamesh.

Diabolos 

The final exclusive Esper, Diabolos, is by far the most difficult to obtain, as it’s found at the veeeeeery end of the Dragons’ Den, the longest and most difficult dungeon in the game. It’s a painful enough process that it has its own article, linked below.

Part Thirty-Nine: Dragons' Den (GBA and iOS only)