Bonus dungeon

Bonus Dungeon, also known as secret dungeon or optional dungeon, is an optional location that is usually much more difficult than the main game with enemies that are much higher level than on other parts of the game. These dungeons are considered sidequests and often contain the most powerful equipment and, sometimes, summons that can only be obtained by completing the dungeon. The boss fought at the end of a bonus dungeon is often a superboss.

A game can have multiple bonus dungeons. Bonus dungeons are common features added to remakes of older games, to give experienced players new material to test their skills against, and to make the remake more lucrative purchase for people who have already completed an earlier version of the game.

Soul of Chaos
Bonus dungeons have been introduced in the remade versions of the original Final Fantasy. As the original Final Fantasy is the most remade game in the series, with the highest number of different versions, it has had plenty of new content added over the years.

Soul of Chaos is the collective name of the four bonus dungeons originating in the Dawn of Souls version of the original Final Fantasy, that reappear in the 20th Anniversary Edition and iOS versions.

Each dungeon is tied to one of the four worldly elements and are initially sealed by a statue of their element's respective Chaos Fiend. Each dungeon, with the exception of Earthgift Shrine, is significantly longer than any in the main game. Major bosses from future games in the series are fought in the shrines and the dungeons include many new and powerful pieces of equipment, as well as enemies that were not in the original game.

Labyrinth of Time
The Labyrinth of Time is the new bonus dungeon in the Final Fantasy 20th Anniversary and iOS versions of the original Final Fantasy. It consists of various floors, each one containing puzzles that must be solved on time for the player to be able to proceed. At the deepest floor of the dungeon players will face Chronodia, Master of Time, the new superboss.

Soul of Rebirth
The Soul of Rebirth is a bonus quest in the Dawn of Souls, 20th Anniversary, and iOS versions of Final Fantasy II. It becomes available after completing the game, after which the player can select "Soul of Rebirth" from the menu. Soul of Rebirth gives the player a party consisting of three party members they had in the past, with the addition of Scott, who join the party with whatever spells, equipment and stats they had when they left the party. Each of the characters' ultimate weapons can be found in the dungeon, and at the end of the quest, the player faces the light half of the Emperor.

Final Fantasy III
There are numerous optional areas in Final Fantasy III that are not mandatory to further the story's progress, these areas provides the party with valuable items which includes weapons, armor, and spells.

Sunken Cave
Located underwater the small island to the extreme southeast of the Surface World, so the party will need the Nautilus that can use its feature to dive into the underwater surface. The Sunken Cave has a wealth of chests containing lots of equipment and a few items.

Saronia Catacombs
This optional area is accessible from underwater in the southeast part of Saronia. The party can fight Odin here in order obtain the Summon spell Catastro, and steal the Gungnir from him, as well pick up some equipment and items from chests.

Lake Dohr
Lake Dohr is found to the west of Castle Argus over a small mountain range, requiring the Invincible to reach it. The party can fight Leviathan here to obtain the summon spell Leviath. The treasure chests here contain a wealth of attack items, as well as some equipment.

Bahamut's Lair
The cave itself is located to the southeast of Vikings' Cove, but the player must cross the mountains to the east of Bahamut's Lair on the Invincible to reach the entrance. The party can fight Bahamut here in order to obtain him as a summon.

Eureka
Eureka contains some of the best equipment in the game. A gateway to it can be found at the bottom floor of the Crystal Tower, but the Eureka Key is required. Doga and Unei unlock the Eureka Key, and give it to the Warriors of Light, granting them access to Eureka, knowing they need better equipment to fight Xande.

???
??? is an unnamed, secret underwater dungeon present in the Nintendo DS remake of the game. In order to unlock the dungeon, the player must finish the Mognet side-quest and retrieve every single letter. Located in the cave is Red Dragon, Green Dragon and Yellow Dragon, which have Onion Equipment as their common and rare drops, and a secret superboss, the Iron Giant.

Lair of the Father


Lair of the Father is an optional dungeon in all versions of Final Fantasy IV where the player can acquire the Eidolon Bahamut. The player can visit the cave as soon as they acquire the Lunar Whale and fly to the Red Moon.

Cave of Trials


The Cave of Trials is a bonus dungeon appearing in the Advance and Complete Collection releases. The dungeon contains eight floors and the final floor contains five weapons guarded by bosses, one for each of the five party members players can swap out. The weapon can only be acquired if the correct member to wield it is in the party. Each of these weapons correspond to the characters who become available after the Giant of Babil to put them on-par with the rest of the group, who can acquire their ultimate weapons in the Lunar Subterrane. However, still stronger weapons can be acquired in the Lunar Ruins.

Lunar Ruins


Lunar Ruins is a bonus dungeon in Final Fantasy IV Advance and Final Fantasy IV The Complete Collection unlocked by completing the game. The floors in the ruins are randomized with ten sets of floors of which the sequence of the sets of floor is fixed. In each set, there are five normal floors and a a sixth gate floor, which contains a save point and a door to each playable character's challenge, except for the tenth set, which leads to Zeromus EG, a new superboss.

The mobile phone version of Final Fantasy IV has an all new "EX Dungeon", which is a remake of the Lunar Ruins.

Challenge Dungeon


Challenge Dungeons are bonus dungeons in Final Fantasy IV: The After Years. Every character with their own tale has one. They become available to explore by talking to Challengingway after the tale has been cleared. The Challenge Dungeons are difficult multi-floor dungeons with powerful enemies and often bosses, but for completing them the player receives a rare item or equipment piece. Challenge Dungeons must be completed multiple times to win all the items they offer.

Gil Cave
Gil Cave exists only in the second world connecting the Kingdom of Bal to the mainland entrance of the Big Bridge. By following a hidden path in the south of the cave, one can find the Gil Turtle Path. It is a completely optional area, and houses a great treasure of gil, as well as dangerous and extremely powerful Gil Turtles, which are usually encountered every third step. The path may be completed multiple times for more gil.

Phoenix Tower


The Phoenix Tower is a thirty floor tower found in the merged world. There are two doors in every floor: one will instantly unfold the stairwell to the next floor, while the other is guarded by a random monster. Every five floors there will be pots on the right and left sides of the screen and one of the pots will contain an amount of GP equal to the floor number multiplied by 1000, and the other is revealed to be a Magic Pot.

All other encounters apart from the Magic Pots are inescapable and the enemies have a tendency to hit the party with strong status ailments. Completing the tower obtains the Phoenix summon to the player.

Sealed Temple


The Sealed Temple is a secret dungeon in Final Fantasy V Advance. It is located underwater, south of Phantom Village, and contains four crystal shards with the jobs of Cannoneer, Gladiator, Oracle, and Necromancer, although the last lies at the end of the Cloister of the Dead. In the temple the players can find the strongest enemies and bosses of the game, including Omega Mk.II and Neo Shinryu.

Final Fantasy VI
In the World of Ruin visiting any areas after obtaining the airship is optional, but doing the areas lets the player recruit new and old party members and obtain espers. Many players consider the recruiting of all playable cast before the final battle as canon, and therefore most areas in the World of Ruin are not really considered sidequests or bonus dungeons.

Cultists' Tower


The Cultists' Tower was built and is inhabited by the Cult of Kefka, a group that worships Kefka Palazzo. The tower is the tallest structure in the game with dozens of floors over four screens of staircases. All offensive commands, except Magic, are sealed, and unless Umaro is brought along, the party is limited to the use of spells and items in battle. At the top lies the unique relic Soul of Thamasa, but taking it causes leader of the cult, the Magic Master, to attack the player.

There are no save points in the tower, and the Holy Dragon, one of the Eight Dragons, resides in one of the tower's treasure rooms.

Ebot's Rock
Ebot's Rock is a location in Final Fantasy VI located north of the town of Thamasa in the World of Ruin. Hidon, a beast that was hunted by Strago and Gungho in their youth, lives there. The cave is dark, and the player only has a small circular area of sight. The player must travel throughout Ebot's Rock, collecting enough Coral from treasure chests that a talking treasure chest will move allowing access to Hidon's chamber.

Dragons' Den


The Dragons' Den is a bonus dungeon in Final Fantasy VI Advance located north of the Dragon's Neck Coliseum on an island with a single tree. Access is given once the player has defeated the Eight Dragons. The player can obtain the most powerful equipment pieces in the game in the den, guarded by the most powerful bosses.

Ancient Forest
Ancient Forest is a dungeon located in the Cosmo Area only accessed with a green, black or gold chocobo, or by defeating Ultimate Weapon first. In the forest the player must solve some puzzles to find rare Materia and weapons.

Sunken Gelnika


The Sunken Gelnika is a crashed airplane that lies on the Bottom of the Sea to the south of Costa del Sol. The plane can only be accessed after the player has acquired the submarine. Even after sinking to the ocean floor, the plane's interior is able to keep from flooding, allowing for one to enter the sunken aircraft from the ocean. Gelnika holds some of the game's most difficult enemies, and also some of its best treasures.

Tomb of the Unknown King


The Tomb of the Unknown King is a location near Deling City and by doing the sidequest inside the player can obtain the Guardian Force Brothers. Most of the areas are tunnels, making the tomb appear straightforward, but if the player decides to backtrack, the viewpoint will change, potentially confusing the player. The player will immediately drop a SeeD rank if s/he decides to venture out of the tomb before his/her objective is fulfilled.

Centra Ruins


The Centra Ruins is an optional location on the Centra continent. Upon entering the ruins, a timer begins and the party must find a series of red gemstones and place them in the eyes of statues in order to acquire the secret code to access the room where Odin is fought. The Tonberry King also appears randomly once 20 or more Tonberries have been killed. Defeating him earns the player Tonberry as a Guardian Force.

Deep Sea Research Center


The Deep Sea Research Center is a hidden island located far out in the middle of the ocean, in the very south-west corner of the World Map. It is an abandoned, half-sunken laboratory which was formerly used to research draw effects. In the first area the player must face Bahamut, and after defeating him and earning him as a Guardian Force, the player can advance deeper into the ruins.

Some of the toughest opponents are fought on the way to the bottom, and on the last floor the player faces Ultima Weapon, who has the most powerful Guardian Force, Eden.

Cavern of the Stolen Fayth


The Cavern of the Stolen Fayth is located in a gorge to the north of the Calm Lands, near the entrance to Mt. Gagazet. The cave hides a fayth that legend says was stolen long ago to prevent summoners from completing their pilgrimage. At the end of the cavern the players will have to fight a boss and they get the chance to recruit Yojimbo as an aeon for Yuna.

Omega Ruins


The Omega Ruins is a large dungeon located within a small group of islands to the east of Spira's main continent. Unlike many of the other locations in the game, the cave must be mapped by the player. At the end of the cave, two deadly bosses await the party's arrival, Omega and Ultima Weapons.

Final Fantasy X-2
Because of the non-linear nature of Final Fantasy X-2, many areas and missions are entirely optional. Completing most of the areas is still needed if the player seeks 100% story completion, although some areas are truly optional, and do not affect story completion percentage.

Ruins Depths


The Ruin Depths is an optional dungeon in the Calm Lands, situated behind and on a lower level than the Chocobo Ranch. Unlike most areas in Final Fantasy X-2, the Ruin Depths does not have a mini-map and contains some rare and unique treasures. The dungeon must be unlocked to enter in a complicated process of chocobo raising and exploration.

The boss of the area is the Anything Eater; once defeated, all five sets of locked doors are unlocked; once they are manually opened, the final door giving access to the Amazing Chocobo is unlocked. A Garment Grid with the constant ability of Break HP Limit is the prize for getting to the Amazing Chocobo. The Ruins are not part of 100% completion or the main quest.

Fiend Colony


The Fiend Colony is an optional dungeon located on the Mi'ihen Highroad. The player must dispatch a level four or five chocobo to the highroad from Clasko's Chocobo Ranch during Chapter 5 to access it. To travel through the dungeon, the player will need to destroy stone walls with bombs. Once the player reaches the back of the cave, they will have to fight the King VERMIN!. Defeating him gets the party a new Garment Grid. Completing Fiend Colony is not needed for 100% story completion.

Den of Woe


Den of Woe is a hidden cave in the Mushroom Rock Ravine that can only be accessed if ten Crimson Spheres are collected during the game. Many of the spheres have special requirements to be obtained and are well hidden. The Den of Woe contains no treasure, but has some boss battles. Although Den of Woe is an optional sidequest, unlocking and entering the Den is necessary for achieving 100% completion.

Via Infinito


Via Infinito is a 100-floor dungeon located beneath Bevelle and in the final cloister the party can challenge the game's superboss, Trema. For each cloister block of 20 floors, there are about 6 level designs which appear at random as each one is completed. The dungeon is swarming with monsters, and equipping a Charm Bangle for No Encounters will have no effect. Every oversoulable fiend, except for the Georapella and Precepts Guard, can be found here. Valuable spheres and accessories can be obtained from the defeated bosses. Completing Via Infinito adds to story completion.

Necrohol of Nabudis


The Necrohol of Nabudis was once the capital of the Kingdom of Nabradia, but its remains have become corrupted by the thick mist that covers the region. The location is not part of the main storyline, and houses the game's ultimate weapon, the Zodiac Spear. The player can access the area as soon as the Dawn Shard has been acquired, which means that the game's ultimate weapon can be acquired fairly early in the game. The Esper Chaos resides in the Necrohol, as do some marks and rare game.

Great Crystal


Even though Great Crystal is visited as part of the storyline, only a small part of it is mandatory. If the player returns after having obtained the Treaty Blade, they can travel into the deepest parts of the crystal. The area has no in-game map, and the interior is like a maze with many dead ends and paths that need to be unlocked. The Esper Ultima and the superboss Omega Mark XII reside within the crystal.

Henne Mines
Henne Mines is a mandatory story location, but its true depths can only be explored after obtaining ten Espers and asking the geomancer in Jahara to open the locked gate within the mines. At the mines the player will encounter some of the toughest regular monsters in the game, and at the end of the mines, battles the ultimate Esper, Zodiark.

Midlight's Deep


Midlight's Deep is a secret dungeon only available in the US and PAL versions of Revenant Wings. The dungeon features the hardest challenges in the game and is located in the Keep of Forgotten Time. It consists of ten levels and the dungeon may be left at any time, though the party must start back at the first level when reentering. On the tenth and final floor resides the superboss Yiazmat.

After completing Midlight's Deep, Vaan's Anastasia sword also gets a boost of +10 in all stats. The stat boosts are cumulative if the player completes Midlight's Deep again.

Faultwarrens


The Faultwarrens is an optional location found in Gran Pulse. It is where the fal'Cie Titan resides breeding more and more powerful monsters and pitting them against the party. Some of the tougher missions are fought here, for a variety of prizes.

Lightning Returns: Final Fantasy XIII
There is a dungeon in the Dead Dunes full of Last Ones and a superboss at its end.

Midlight's Deep


Midlight's Deep is an optional dungeon located on an island east of the Port City of Warjilis. It consists of ten levels of caves and is home to the most difficult enemies in the game, and the best treasure through the Treasure Hunter ability. From the start, only one of the ten levels can be accessed. In order to get deeper, the player must fight a battle, all of which function like random battles.

Simply defeating every enemy on the screen will not work, instead, the player must find a passageway which leads to the next level. This passage is always hidden in one of five different squares on each floor and to find the exit, a unit only needs to step on that square. The tenth level holds a regular storyline battle with the secret Lucavi demon Elidibus, who uses the secret summon magic that can only be learned from him.

Brightmoon Tor
Brightmoon Tor is a set of bonus dungeons in Final Fantasy Tactics A2: Grimoire of the Rift. Some of the strongest enemies in the game reside in these dungeons. At the top of each Brightmoon Tor location is a watch. These watches have enemies at level 90 and above. Although the items the dungeons contain may only be obtained once, multiple attempts can be made to retrieve them. If one failed to notice them the first time, or simply did not have the required equipment, one can try again.

Final Fantasy Legend II
There is only one bonus dungeon in the game, Nasty Dungeon, and it lives up to its name. The monsters comes in a large variety of groups, and the dungeon branching pathways with no real indication as to which path is the correct one. Enemy groups can easily reach up to fifteen, more or less monsters per battle, and surprise attacks can become quite a constant threat inside this dungeon. But the treasure found inside is well worth the player's effort.

Final Fantasy Legend III
There are quite a number of optional dungeon to explore, and they are found in various areas. But some of them becomes inaccessible after a certain point. The dungeons are fairly simple to navigate and contains valuable treasures.

List of Optional Dungeons:
 * Shipwrecks
 * Mushrooms
 * West Tower
 * Caves
 * Shedding of Jorgandr

Final Fantasy: The 4 Heroes of Light
Final Fantasy: The 4 Heroes of Light has four bonus dungeons: Holy Tree Tower, Moonsand Ruins, Mysterious Lighthouse and Trial Tower. They become available after the player obtains the Master Key. Each tower is 100 floors tall with special floors every 10 floors where the player can leave the tower to save. Sometimes the special floors have bosses or a merchant or a treasure chest. Some of the best equipment can only be obtained as random treasures in the bonus dungeons.