You will not be able to reach the Deep Sea Research Center until you have access to the Ragnarok ship, which means you’ll need to have completed both the Lunar Base and Ragnarok portions of the story. Use the links below to return to those sections of the walkthrough if you need to:
31) Lunar Base
Exploring the Lunar Base to find Ellone.
32) Ragnarok
Clearing out and obtaining the Ragnarok with Squall and Rinoa.
Once you have access to the Ragnarok, its time to head out to the middle of the sea. The Deep Sea Research Center is not located on the world map but you can find it by flying down to the lower left corner of the map. Use the screenshot and map below to help you find it:
There are a total of two side quests and one area you can farm for raw materials while you are at this location. Follow the guide below for information on each.
This first level of the Deep Sea Research Center is called the “Lab”. Your team will notice that the location looks like its been abandoned for years and will start to question what the big blue light (the core) is in the center of the room. A voice will say “The blue light leads all to death. Turn back…” which is your clue on how to navigate through this first room.
All you have to do is walk towards the core whenever the bright blue light goes dim or turns off. If you move while the light is flashing you will be thrown into an encounter with a random monster.
Most of the enemies in these areas are easy to manage and defeat, but the Ruby Dragons can prove to be a bit more problematic and you will be fighting quite a few of them, if not during these random encounters, then during a few fixed battles that will be coming up.
You can make the fights against the Ruby Dragons much easier by ensuring that you do not have fire-based magic, such as 
Firaga, junctioned to any of your character’s weapons. The game likes to default Firaga as an elemental attack, but attacking a Ruby Dragon with a regular weapon-based attack while you have fire-based magic junctioned will heal it. Instead, junction ice-based magic such as Blizzaga.
Additionally, to make things even easier, you can junction fire-base magic (Firaga) and wind-based magic (such as Tornado) to your character’s armor using 
Elem-Def-J and this will negate many of the dragon’s attacks.
You should also make some additional preparations for an upcoming boss battle, as once the dialogue boxes kick up, you won’t have an opportunity to fix and correct the junctions of your party members.
As mentioned above, consider junctioning wind-based magic (Tornado) to your character’s armor, and also consider junctioning lightning-based magic as well (Thundaga). Make sure that, in addition to not junctioning fire-based magic to your weapon as noted in the helpful hint above, also make sure that you haven’t junctioned lightning, earth or wind-based magic either.
Use the ST-Atk-J ability to junction Save Point, Draw Blind magic to one or more of your characters as well.
You will probably find yourself in a few battles accidentally but this won’t cause any problems with the side quest, it just means your journey towards the center core will be a little bit slower.
Once you get to the core a window will prompt you to choose a response to the statements and questions being asked by the voice. The questions and responses are below:
Now its time to fight Bahamut, your next Guardian Force!
In Game Description: Called the King of GF; its Mega Flare ignores all defense. Gives assistance freely to those who show their power.
This battle is already fairly straightforward, but if you took steps to complete the preparation noted above in the helpful hints, this battle will be even easier.
Bahamut will attack with Thundaga and Tornado, which won’t do too much damage, and then will hit you with regular physical attacks. It is susceptible to Blind magic though, so if you’re able to Blind it, none of its physical attacks will hit, nearly negating all of the damage it can do.
It is, however, capable of using a move called Mega Flare, which will do quite a lot of damage to your party, but you can likely defeat Bahamut before it gets a chance to use this move.
Other tips that will help speed up the battle include using Meltdown on Bahamut, and casting Aura / Haste on your party members. You can also cast Slow on Bahamut if you need to.
Bahamut
You will receive the Bahamut Achievement/Trophy once you defeat Bahamut at the core and it joins your team as a Guardian Force.
Congratulations! You now have Bahamut as your new Guardian Force! Bahamut has a number of important abilities for you to learn. Most importantly, it comes with Abilityx4 already learned. Have Bahamut focus on learning 
Mug first, and then focus on the following abilities:
Bahamut also has an ability that it can learn called 
Rare Item. At a casual glance, this ability looks like it should be extremely beneficial, offering you a higher likelihood of receiving a rare item at the end of a fight. But unfortunately, with the way that the loot tables in Final Fantasy VIII are structured, this ability will actually have a net negative impact on the rarity of the items you receive. Its time for some charts:
The typical enemy loot table looks like this:
Equipping the Rare Item ability changes the table to this:
So this ability has the potential to increase the chances of you obtaining a more uncommon item but will actually reduce your chances of potentially receiving the most rare of items. This ability is viewed as a net loss when you use it. So don’t!
Exit the Lab section of the Deep Sea Research Center and then re-enter this area and a Save Point will appear. Use the Save Point to save your game before you continue.
Before we proceed with the remaining side quests in the Deep Sea Research Center, its important that we spend a bit of time explaining why a player may or may not want to proceed to the bottom and obtain their last Guardian Force, and this has to do with Tri-Faces and, more importantly, the item that they drop, 
Curse Spikes.
Check out the Fixed Encounters with Tri-Faces Section below for more information:
The remainder of this guide is going to explain how to get to the bottom of the Deep Sea Research Center, defeat Ultima Weapon and obtain your last Guardian Force, Eden (and the 
Eden Card). This is done with the assumption that you are okay with no longer being able to farm Tri-Faces for Curse Spikes.
Once you defeat Ultima Weapon (to obtain the Eden Guardian Force) you will no longer be able to trigger automatic encounters with Tri-Faces to obtain Curse Spikes. That may be completely okay, and you can farm a fair number of them before you decide to continue with the game, but perfectionists and completionists will often avoid defeating Ultima Weapon because you can obtain Eden elsewhere in the game (from a boss in disc 4 in Ultimecia’s castle).
For many players, retaining a method to farm Curse Spikes is completely unnecessary, but its important to note that defeating Ultima Weapon permanently removes this extremely efficient farming method and you technically don’t have to kill Ultima Weapon for any in-game purpose (i.e. nothing will be missed or lost other than you won’t get Eden as early).
The choice is yours!
Its time to begin working our way to the bottom of the Research Center. As noted above, make sure you saved your game, but make sure that you have Zell in your party as you go down these next sections.
Make sure Zell is in your party. Whether you plan to defeat Ultima Weapon or skip this section of the game for now, you’ll want to have Zell in your party to make sure that you have enough steam at the bottom of the Deep Sea Research Center.
Once you reach the area with the fixed encounters with Tri-Faces, you’ll find a Save Point where you can swap Zell back out of your party before you begin farming Curse Spikes.
The game will give you a brief explanation of how the “Current Research Steam Pressure” system works, but its fairly straightforward, so don’t worry if the game’s explanation didn’t make much sense.
The general idea is that you want to reserve as much of the Steam Pressure as you can as you go down each level, and having Zell in your party is going to give you an added extra bit of steam that you will need in order to activate the machine at the end of the path and initiate the fight against Ultima Weapon.
This is another great opportunity to make use of Diablos’ Enc-None Ability. Having this ability equipped on one of your characters will ensure that you don’t encounter too many random battles while you’re travelling through each of the areas of the Research Center.
You start off with 20 our of 20 Reserve Steam Pressure and each time you open a door it will cost you some of that steam pressure.
Open the first gate and move down to the second level. Examine the terminal on the second level and choose to use 1 Reserve Steam Pressure (RSP). Go down to level 3 and, once again, choose to use 1 RSP. Continue using 1 RSP for each of the levels until you get to the bottom.
When you get to the bottom level Zell will offer to “take care of this machine” for you. Choose to allow him to by selecting the (“Well… Zell’s pretty good with machinery”) option. Zell will then begin fidgeting with and eventually just outright beating the crap out of the machinery.
He will manage to open the last door for you and save you some RSP (as you’re going to need at least 10 at the bottom if you wish to engage Ultima Weapon).
Walk towards the Save Point and you will immediately be thrown into a battle against a Tri-Face, even if you have Diablos Enc-None equipped. This is the very first fixed encounter of the Deep Sea Research Center.
There are quite a few more coming, but this is where you would farm Curse Spikes if you wish to, and this is highly recommended even if you aren’t planning on trying to perfect all of your characters and their stats.
Use the Save Point to swap Zell out of your party if you need to.
This is as far as you will need to go if you are not planning on defeating Ultima Weapon and obtaining Eden at this stage of the game. Read the warning up above for more information, but you can stop here and stay in this area, before eventually heading back up. Check out the Fixed Encounters with Tri-Faces (Curse Spikes) section for more information.
Check out the Fixed Encounters with Tri-Faces (Curse Spikes) section below for some useful tips on how to procure Curse Spikes more efficiently (if you are planning to pick some up):
For those players that are not planning on playing a perfect game or maxing out character stats, and want to see Ultima Weapon and get their new Guardian Force, continue on…
The remaining levels of the Deep Sea Deposit also have fixed encounters that you will have to deal with. The second level has Grendels and Imps, the third level has Behemoths, the third level has Ruby Dragons and the last level has Iron Giants. Here are some tips for the upcoming battles:
Grendels and Imps
No advice or strategy is required for these enemies. They are very easy to defeat.
Behemoths
The Behemoths deal quite a bit of damage with some of their attacks, but they are completely susceptible to status effects such as Blind, Silence and Bio. Consider using these to make the fights very easy.
Ruby Dragons
These are probably the hardest battles, but the strategy is the same as what you’ve faced before. Just be extra cautious because they have a move called “Breath” that deals a ton of damage to all of your party members.
You can use Shell to greatly reduce the damage that this deals. Also use Meltdown to reduce Ruby Dragon’s high armor so that your attacks hit for much harder. Finally, you probably don’t need this reminder, but make sure that you don’t have fire-based magic equipped to Elem-Atk-J.
Iron Giants
Battles against these enemies are a true fight of attrition just due to how much HP they have. Start off by using Meltdown on both of them and casting Blind on both of them. This will have the affect of reducing their armor and increasing the amount of damage that they take, while Blind will entirely prevent them from doing any damage to you at all (since all of their attacks are physical).
They will sometimes cast a magic spell called Mighty Guard. You can use Dispel to get rid of this if its reducing your character’s damage too much.
At the bottom of the Deep Sea Deposit is a mechanical device with a red screen perched above the water. You will need to have 10 or more RSP to activate the device. As soon as you do, you will be thrown into battle against Ultima Weapon. To prepare for this fight, consider adding the Revive Ability to one of your character.
In Game Description: Strongest, ultimate monster. It is said to be impossible to defeat.
The first and most important thing to remember to do is to use the Draw command and grab your new Guardian Force, Eden.
Ultima Weapon’s most powerful attack is called Light Pillar. This attack will deal 9,999 damage to whomever it hits and there is no way to reduce or mitigate this damage. So in other words, Light Pillar is an instant kill that cannot be prevented. It can also cast a move called Gravija which deals damage equal to 75% of a character’s HP (just like Demi, it cannot kill a character).
Set yourself up so that you can revive your party members easily. Use the Revive command, as mentioned above, or Full-Life magic, to bring your KO’d characters back into the battle.
Here are some tips to help bring Ultima Weapon down:
Aura magic on your party members so that they can use Limit Breaks without having low health. Specifically, Squall’s Renzokuken attack is extremely powerful.Meltdown on Ultima Weapon to reduce its defences to zero, subsequently increasing the damage of each of your attacks.Be liberal in your use of 
Megalixirs, Elixirs, Mega Phoenix, and any other items that you have available. You can also cast Cerberus to give each of your players Haste (although once they get KO’d by Light Pillar you will have to recast it), and use Protect and Shell˝ (or 
Auto-Protect and Auto-Shell) to increase your character’s defences if you need it).
Eden
You will receive the Eden Achievement/Trophy once you have successfully drawn Eden from Ultima Weapon and then defeated Ultima Weapon.
Congratulations! You’ve defeated Ultima Weapon! Your prize for the successful victory? Having to climb all the way back up out of the Deep Sea Research Center. Enjoy the trip back up… I guess.
This concludes the side quests that you can complete in this subsection of the game. If you completed this side quest as soon as it became available, after you obtained access to the Ragnarok, use the link below to return to that section of the strategy guide:
Hyper Wrist
Forbid Mag-RF
Ultima Stone