Please apply the "Alternative Omega Weapon Steal And Drop" patch located in the Optional Patches folder to your EX rom if you wish to change Omega Weapon's steal to a Megalixir and his drop to the Omega Weapon (both are normally Dagger, the default item for monsters in FFVI). This is NOT intended normally, but I wanted a fun reward for players if they decide to go hunt this guy down.

Hidden deep in EX is a secret boss fight that until recently we weren't aware existed. Since the EX patch is based off a very old version of 
T-Edition, alot of content has since been removed, repurposed, or changed completely. One such content is the Dragon's Den, faithfully recreated from the GBA content, located north of the Dragon's Neck Coliseum. In the base T-Edition file, currently this is the location of the 3-layer super dungeon, the Labyrinth of the Ancients, Forbidden Land Eureka, and the Crystal Tower.

To get out of the EX save room and begin exploring, simply just save your game on the world map, say, outside Narshe and then load your save 
file into the EX patch. Be careful, and please read on, as most of the stuff below applies to the game world within.

I'd like to thank Maxtory9999 for discovering this originally, as we never fully explored the dungeon, let alone assumed there was a boss 
fully coded still. See his discovery here: https://www.youtube.com/watch?v=6M3x9TP98XY

So with that, if you've fully conquered the EX patch and T-Edition, and want one last challenge, there's Omega Weapon.

While the dungeon is mostly fully coded, and can be traversed with little issues, there are some things you need to be aware of if you go 
delving into this, looking for the super boss, Omega Weapon, at the end which is fully coded and fightable.

Note: Of the 3 switches at the end, whatever party you want to use to face Omega Weapon, have them step on the switch last.

- At all times on the EX patch make sure you have someone using Molulu's Charm. Most to all random battles are garbage data due to Tsushiy's 
coding for the EX patch and you will soft lock/crash upon entering a fight.

- Don't talk to flame NPCs in the dungeon or you'll crash. You can safely bump into them and nothing happens.

- Ghost NPCs can bump you off the bridges no problem.

- The turtle NPC you encounter, you have to goad it to the center by clicking the water, then loop around to travel/jump to the west, 
otherwise you can only travel/ride him north and south.

- Any blank text boxes just click through, they won't crash you. This includes trying to fly the airship.

- After Omega Weapon, if you use the teleport behind him to exit, it'll black screen. Hold left and mash the A Button or whatever you have 
confirm set as to take control of the airship and regain visibility of your game.

Once done, simply save your game some place safe, such as outside Narshe and load back into T-Edition to properly continue your journey.