Like one retro dungeon or multiple dungeons per patch thing from FF1 to FF9
Also the dungeons will play exactly like it did from the their respective games (except ones have to be translated from Pixel to 3D environments). So no hallway Dungeons in the FFXIV style, and monsters will spawn randomly rather than being in a particular spot to honor the original.
Also it fit well with the Adventurer just looking for a good ol' time exploring the world (no big bad villains to worry about..well ok just a couple of big meanies).
My Picks!:
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Darill's Tomb (FFVI)
Maybe have the Adventurer seek out a lost Airship
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Ancient Castle (FFVI)
The Adventurer hears about a Primal that once buried a entire kingdom underground. Maybe have Odin and Raiden be connected to it like it was originally in FFVI.
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Narshe Mines (FFVI)
The Adventurer learns of a Abandoned old Mining Town somewhere north of Garlemald that can be reached by Train Tunnels.
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Tomb of the Unknown King (FFVIII)
The Adventurer is recruited to learn of a lost king on The First, and recover its history, but its guardian is harassing anyone that dares draw near.
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Fossil Roo (FFIX)
The Adventurer is recruited to find out where certain creatures come from, particularly of the prehistoric variety that the Adventurer has fought time and time again, maybe some answers lay in Fossil Roo?
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Evil Forest (FFIX)
The Adventurer is recruited to find out what is causing people to become petrified, and eliminate the source.
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Mirage Tower (FFI)
Somewhere in the Nhaama Desert speaks of a mysterious tower that appears and disappears when one gets too close to it. People report seeing unknown Magitek unlike any that has been seen before.
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Marsh Cave (FFI)
A simple dungeon that speaks of lost treasure, I was thinking maybe place it where Moondrip is in Western Thanalan or hidden somewhere in Mor Dhona.
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The Cavern of Earth, Sunken Shrine, Mount Gulg (Either on the Source or maybe a re-visit on the first), and Flying Fortress all with respective original Fiend (FF1)
Ancient creatures chaotically spawned during the Ancient's Final Days, sealed away by the ancients long ago to not trouble Etheiryis anymore, the seals are now weakening and the Adventurer will have to put these ancient terrors down.
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Midlight's Deep (FFT) Also a nod to Elidibus who was the superboss in it.
I was thinking as a twist for this that one could make this like the first 10-floor dungeon of FFXIV, fun dungeon similar to Deep Dungeon with a big boss at the end.
I was thinking the superboss should be Ophiuchus/Serpentarius (since we can't use Elidibus here obviously), and it was a sealed away Lucavi Beast by the elementals during a unknown time in Gridiana, and a ancient legend amongst the Duskwight Elezens. It would also connect it to the Gridianian Flag.
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Zozo (FFVI)
A Fallen City State overrun by criminals & strange monsters, their leader is causing problems in the surrounding land and the Adventurer will need to put a stop to it (might give them a excuse to use that Dadaluma Model again from the Omega Raids). Not sure where you could put this in Ethierys.
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Owzer's Mansion (FFVI):
Adventurer learns about someone trapped inside the haunted mansion of Owzer, and goes to rescue her (A FFXIV version of Relm). I was thinking a remixed battle with Chadarnook from the Omega raids.
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Phantom Forest (FFVI):
I was thinking appropriately this forest should be near Doma since it is related with it in some capacity, maybe during Gosetsu's travels he learns of a haunted Forest that needs to be excised of spirits turned monsters that have trouble moving on. A remixed battle with the Phantom Train from the Omega Raids here as well.
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Temple of the Ancients (FFVII):
I was thinking the Temple of the Ancients be buried in a underground cavern under the city of Mhach, remnant of the Ancients of Etheirys housing the Black Materia that can summon Meteor to completely devastate the landscape, but runs the risk of quickly using up a lot of aether in the land, its purpose was to protect the temple from extreme threats deemed uncontrollable. It was later discovered by the Mhachi and thus why the City was built on top of it, and kept secret from the rest of the world. It was planned to be used to along with the Voidsent, but never came to fruition when the elementals devastated all the city states.
The Adventurer is called by the Sky pirates for one more delve into Mhach after discovering new ruins, and delving into its depths to find what waits within.
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The Great Glacier - Maybe somewhere in Garlemald or in a future location (FFVII)
There is a lot of field to explore with this place, and with its boss Snow (I wonder if it was supposed to be called Yuki-Onna at the time)? I think a place with a time limit before you freeze to death would be interesting take unless you get to the hot spring in time, it would have adventurers making sure to help each other when exploring around.
I'm going to break my rule here for this one since I believe the developers could a lot with this one to make it really fun instead of how it played in Final Fantasy VII.
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D-District Prison (FFVIII):
I was thinking the best way to translate this would be like its a abandoned Garlean Prison for Political Prisoners in another country with a desert somewhere, maybe have the Adventurer help a group of Garleans for whatever particular mission they need to do here.
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The Great Salt Flats (FFVIII)
Hmm well, given its all salt, so in FFXIV this would mean a aether-dried land, the only place I imagine where you can put this would be somewhere near The Burn as its the only known area that was completely depleted of aether.
We didn't get to explore the Burn that much, so it would be cool for a re-visit to another part of it, maybe have the Great Salt Flats be Allagan related.
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Lunatic Pandora (FFVIII)
Since Lunatic Pandora is related with the moon in FFVIII, I'm thinking in two ways to introduce this:
A prototype Fortress Weapon meant to be used in conjunction with Dalamud to be used against the enemies of Allagan, but ran into issues that caused Lunatic Pandora to never be used, the Adventurer learns of it and explores the Allagan Ruins to help record lost history for the Sons of Saint Coinach.
or
Lunatic Pandora built by the Allagan Adel to be used in conjunction with Dalamud to usurp Emperor Xande at one point in time, but failed to do so, and Adel was sealed away inside Lunatic Pandora as punishment for his transgressions and erased all history related to this incident. Now he begins to stir and awaken again to rule the world once more and the Adventurer will need to put him down before he can do so.
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Citadel of Trials (FFI)
A place to test their courage somewhere located in Meracydia, built by Bahamut and his people.
The Adventurer learns of a place where he can test his skills and wits, and this place is the perfect place for someone like the Warrior of Light.
I was thinking for this dungeon, each job gets a special exclusive class item upon completion, and The Rat's Tail (which isn't used for anything, but as a furniture piece to prove you have courage)! Since this dungeon does not have a boss, I'm thinking some variation of a FFXIV Dragon Zombie would be appropriate here (and Meracydia was already devastated, and we know dragons live there).
I know this dungeon had a lot of puzzle teleports, and can be memorized the first time around, so breaking a rule here where the teleports will change each time you visit.
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labyrinth of Time (FFI - Anniversary Remake):
If anyone who had played this dungeon would know there is a lot going on in it that would give this dungeon a lot of replay value from a MMORPG perspective, and fighting different variations of Chronodia would be neat. I can see this being a like modified Variant dungeon with some deep dungeon gameplay aspects, but playing exactly like Labyrinth of Time and would be longer to complete due to how the routes would work, the puzzles, your abilities being locked, etc. For more information check out the wiki for it since there is a lot to explain the mechanics behind this dungeon.
Also from a developer perspective making the four original fiends & their dungeons earlier in my list would make this a bit more streamlined into Labyrinth of Time's Dungeons layouts and its Boss Chronodia since it absorbed the Fiends (I think), and the devs would already have the models to merge with Chronodia in various spots.
I'm thinking how to fit this into FFXIV would be if the Adventurer, Omega, and the Omnicrons discover something of interest in Ultima Thule that leads to a portal to another Dimension leading to the Labyrinth of Time...(that is all I can think of honestly).
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Deist Cavern & Castle Deist (FFII):
I gave your suggestion some thought SilverObi, and I think this would perfect for that mysterious Doorway in the Dravanian Forelands (and I hope the Devs would consider it)!
It will lead to a place called Deist Cavern, housing a sacred spring once home to Dragons and their Dragon Eggs, it became sealed away during the many battles with Ishgard, there is a tunnel within the caverns that leads to abandoned Castle that belonged to a forgotten High House called Deist that was led by a man named Ricard during the time when Man & Dragon lived in peace.
The Adventurer is tasked of recovering lost history for the Dragons & Ishgard from this abandoned place.
The Boss in Deist Cavern was a Chimera, but Castle Deist didn't have a boss, so I'm thinking making the Gigas as a boss should work
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Mysidian Tower (FFII):
The Mysidian Tower was a forgotten place where Black & White Mages did live together that rejected the War of the Magi, and from there they sealed away many magical tomes so that the past could never repeat itself in the future ages to come, a few individuals sacrificed themselves to become eternal elemental monstrous giants so that nobody can enter its abandoned halls.
Adventurer is tasked by the associated NPCs from the BLM & WHM quests to investigate the recently discovered Tower to learn of its history, and figure out what to do with the fate of the magical tomes.
I'm thinking the best place to put this is over somewhere in Ala Mhigo, maybe a place we as players never really investigated during Stormblood, and there was some evidence of the Flooding over there, so it should work out from a lore perspective.
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Memoria & the Crystal World (FFIX):
hmm idk what you can do with this, but I read it mentioned on here by Absimiliard...the problem with this dungeon is very story related with FFIX, and you'll have to make it entirely be the memories of FFXIV and related with the Crystal (and FFXIV's Crystal was used for a entirely different purpose for this world).
I suppose if the Developers would to play around with the Lifestream a bit more then you could make Memoria happen, I suppose a FFXIV version of Necron could work here, and maybe it will play out the same way like it did in FFIX. He will regard everything on Eithierys wanting death, and so he'll stop the flow of the Lifestream to make it happen.
Maybe have Necron remark how the Warrior of Light has killed so many as well, and how other powerful beings have done so as well throughout the ages, thinking that death is what everyone seeks. A deity born from many souls that died violently that live inside the lifestream that couldn't move on.
It would be interesting to see how the Warrior of Light reacts to the many faces he has slain and even Side-Quest Villains.
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Great Sea Trench (FFV):
I can see this happening for the upcoming Dawntrail as a setting for this one, but a dungeon where you fight those creepy unknown monsters from FFV would be cool, and those three weirdos Triton, Nereid, and Phobos.
Definitely would be a interesting Retro Dungeon.
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Zone Eater's Belly (FFVI):
Ok hear me out on this one, but this would be a funny Dungeon the devs could do if you let a certain monster eat you and you wind up in this special dungeon. I'm thinking the boss should actually be XIV's Gogo! Maybe make this Dungeon the first accessible Dungeon for Blue Mages on Duty Finder to join with other jobs on (so it will be on roulettes, etc too).
I'm thinking the access to this dungeon can be done like this:
Its accessible once you do the battle with Gogo during the Blue Mage Questline
Gogo mysteriously disappears one day, and the Adventurer has to find his last location somewhere in the Burn (its the only place I think of where you can fit a Gigantic Worm like the Zone Eater at).
Fight Zone Eater solo with NPCs and win, and the Zone Eater will suck you in
This will open up the Dungeon.
Once the Adventurer finds Gogo inside the Zone Eater that it turns out he is just fine, and was looking for new skills to learn and test on you. This will make this a 4-man battle rather than the solo battle back earlier in the BLU Questline.
Gogo's Dungeon in FFVI was pretty funny, would love to see a 3D rendition of that.
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Underwater Reactor (FFVII):
Could possibly make this like a Garlean Project now abandoned, and taken over by a voidsent called the Ghost Ship (he wasn't a boss, but he is perfect for one) and a malfunctioning Carry Armor rampaging inside the Underwater Reactor. I think it would be interesting to explore a bit if Garlemald ever did experiment with underwater ships, and such since Garlemald was all about Airship power. Maybe this underwater project was a test to see the validity of underwater combat submarines, but was abandoned in favor of Airships.
Have the Adventurer be requested by Garleans to see if their one and only Prototype underwater Magitek Submarine survived over the many years for exploration use of Ethierys oceans.
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Ancient Forest (FFVII):
I think dawntrail would be perfect for a place like that, nothing more to say on it, just a good ol treasure hunting dungeon.
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FFXII Dungeons
I'll comment on this, tbh I think any dungeon from that game could work instantly well inside FFXIV as a retro dungeon since the dungeons how those were designed should theoretically be compatible with FFXIV with some modifications as open field dungeons.
Personally I wouldn't be surprised if we see the return of most of it at some point because of the existence of Ivalice in FFXIV, and we have yet to actually explore the rest of it.
Personally I wouldn't mind fighting some perfected form of Ultima the High Seraph inside a Great Crystal (that would be a fun and dangerous dungeon to do).
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Shameless Plug - Xenogears Crossover Dungeon or Trial please.
Square Enix...I need it...I thirst for it. (XD lol)
Edit - Alright I can't think of anything else for the moment, I had a lot of fun with this topic.