The Mugen(Infinite) Dungeon


Some information on the Version 2.00 Mugen Dungeon.

This is the Random Dungeon that was added in Version 2.00. Its place where monsters of up to Lv2000 spawn and Rank 11 & 12 Weapons can be found (mostly). The boss and mobs for each floor are randomized and the only way to progress deeper is to beat the floor boss that guards the gate to the next floor. The deeper you go, the better the drop rates and drop quality gets. Offline, you can choose to jam in the Infinite Dungeon in Easy mode for some super quick leveling and weapon gathering. Online, you can play with up to 16 players and tackle floors with large raid teams.

There are also a lot of interesting things like Enigma’s and Regulations that keep this dungeon feeling fresh. This post is just a small primer on what to expect in the dungeon as well as some good things to know going into it.


  1. Dungeon Difficulty
  2. Entering & Leaving
  3. Enigma
  4. Regulation
  5. Warning Floors
  6. Kinds of Monsters
  7. Kinds of Drops
  8. Preferred Teams
  9. Prepare Yourself Now

-Dungeon Difficulty-

This Dungeon is incredibly difficult. Its the hardest thing in the game by far. Its so hard, it makes the Death and Accel Assault Extra Quests look like a bag of well trained puppies. Even on Easy Mode offline you can still die really easily if you lose focus and run into an Eyfura or Charon. When it comes to online, progressing through this dungeon with smaller teams becomes one hell of a task.

This is amplified by the fact that if you die and give up (or just get your whole team wiped out offline), you lose every single item you gained since you started the dungeon.

It doesn’t sound like much now, sure, but when you get a sick Max Attack; Half Element Rank 12 1Hand Sword on 126F only to be killed on 127F and lose it is seriously painful. That’s the kind of thing that scars you as a player and you’ll either throw your toys and complain non-stop or suck it up and get better.

Now, some of you might be thinking “Pssh. Yeah right. I’m gonna just find ways to cheat the system so I can keep my drops.”

I thought that too.

Then I tried everything I could think of: Disconnecting the internet, filling your inventory so drops go to storage, trying to over strain my connection to purposefully get disconnected, getting kicked from the room.

Nothing worked. Some of my friends were able to get disconnected and keep their drops, but I wasn’t able to do that. When I get disconnected, I almost always lose everything (>.<)

You’re welcome to go ahead and try different ways to get disconnected but I’ve given up and accepted reality.

Aside from the constant fear of losing items, the dungeon itself is seriously hard. Every boss does 50% damage for sneezing and getting one-shot is a common occurrence regardless of your HP and Defense stat. Sometimes you even get killed by an angry Nemean Lion on your way to the boss.

Prepare to see the “YOU ARE DEAD” screen really often unless you learn how to read attacks and play cautiously.

Other than normal run-of-the-mill bosses becoming overly lethal bastards that can kill you on almost any attack, there was 2 new kinds of Super Bosses added in this update as well, namely Providence & Satanachia (Sacchan). These ones have a chance to appear on every 10th floor and boy, they’re though. They’re not traditional SAO bosses but more like serious raid bosses where you need tactics and an efficient team to win.

Providence is a floating eyeball and he has 4 mini-eyeballs around him that need to be killed before his main body can receive damage. The mini-eyeballs come back after some time so you need to try to kill him as fast as you can when you can damage him. That’s more easier said than done though because Providence has a well equipped array of annoying attacks and he somehow becomes more dangerous when his mini-eyeballs are dead. Trying to tackle this boss with a 2man team is God Eater +99 levels of difficult. In this fight, taking damage is unavoidable because there are tons of little projectiles flying around so Healer teammates become really valuable.

Sacchan is a huge Dual Wielding demon-king. He’s more straightforward than Providence but he’s also extremely annoying because he attacks non stop and almost never gets stunned or DOWNed. His HP and Defense are also incredibly high so fighting him takes up a lot of time. When you have Sacchan’s aggro, there’s not a lot you can do besides blocking and countering his attacks. But even so, his block-strings are so legit your Guard will get broken if you aren’t careful.

However, if you tackle this Mugen Dungeon and these new bosses with large teams, you probably won’t feel such a crushing challenge. Whether that’s a good or bad thing depends on you as a player.

Its not that I recommend using large teams over smaller ones, I’m just trying putting the difficulty curve into perspective.

In my case, I’m addicted to High Difficulty stuff so I know I’m gonna spend a lot of time training to solo through floors and even try to kill Providence and Sacchan by myself.

-Entering & Leaving-

You can enter the Mugen Dungeon and start on 10 floor intervals up until floor 101. To be able to teleport into the dungeon, you yourself need to have been that deep before. Whether its offline or online, you can only teleport to floors you have already cleared.

For example, imagine me standing around on 800F. You wouldn’t be able to teleport to where I am unless you have been to 800F already (whether offline or online).
But if you were derping around on 134F, I could hop out at 800F and teleport to where you are right away.

You can only leave the dungeon every 5 floors. Every 10th floor has a super boss, you need to seriously consider leaving when you have the chance to. After all, dying and choosing to return means you lose everything.

The one downside to offline play, is that once you leave the dungeon, that’s it. Your conquest ends. But when you play online, you can leave someone in the dungeon while you take turns leaving to go save and then come back and start clearing floors again without worrying about losing drops.


For each floor there is a special “ENIGMA”. In this game, the enigma is a hidden requirement that you need to fulfill in order to receive a reward. The requirement is randomized and its always mystery but the “ENIGMA” symbol on the screen lights up when you perform the correct action. Clearing Enigma’s awards you with a special Enigma Chest that appears in the respective floors boss room. These Enigma Chests can give you anything from Rank 8 to 12 weapons to common or rare materials.

List of Enigmas:

  • Perform 10 Dash Attacks
  • Perform 3 Instant Blocks
  • Don’t move for 15 seconds
  • Perform 10 total Skill Connects
  • Kill 5 of a certain mob.
  • Destroy 3 breakable objects (sometimes the color/type of the object matters)
  • Receive 2 rare drops
  • Find one Gold Ball pickup in the floor
  • Use the in-game chat 2 times
  • Use 2 items

All players can work towards Enigmas on floors. If there are 10 of us and we all do one Dash Attack, that respective Enigma will be fulfilled.

Offline, enigmas are a little harder because you have to manually do each of them yourself but that’s how offline is.

**Enigmas don’t appear on 5th and 10th floors


For each floor there is also a “REGULATION”. These are typically a buff, debuff or status ailment that is the rule for that floor. Regulations affect both allies and monsters and the kinds of regulations you can get is also randomized on each floor.


  • On floor 112F, Party will be inflicted with Curse and all Monsters will have Attack Up.
  • On floor 123F, Party will have Defense Up and 10x BP/Rare Drop rate

Regulations are just something you have to put up with on each floor. You cannot remove regulations so you should always be conscious of it.

When nasty regulations come into play, try not to play recklessly. If Abaddon has Attack up and you don’t notice, get ready to be taken to One Shot City.


There are “WARNING” floors that sometimes appear. These are floors that have the hardest and most angry mobs in the game as well as one of the most difficult bosses all in an enclosed space the size of the Arena in town.

Picture a tiny room full of Wights, Sky Creepers, Air Drakes, Nemean Lions and Death all Lv2000.

These are the Surprise floors that make everyone exclaim “Ah Fuck! It’s a Warning Floor!” Its super easy to get robbed of all your weapons on these floors so healers need to be awake.

Warning Floors don’t occur very often so its easy to forget about them. But sometimes the AccelSword Gods get tired of you and send you 2 Warning Floors back to back so always keep it in mind when you are about to jump into the portal to go to the next floor.

**If you are able to complete an Enigma on a Warning floor, you will be awarded with 3 Enigma Chests.

-Kinds of Monsters-

The kinds of mobs and bosses are all randomized but certain ones appear really frequently while others I haven’t even seen in all my hours in the Mugen Dungeon. The most common bosses are Munin, Nanna, Hrungnir, Siegfried, Bergelmir, Aurboda, Bergrisi and Borr.

Every 5th floor will have an upper tier difficulty boss appear like Eyfura, Arngrim, Death, Chernobog, Ruhiel or Farbauti.

But since the Dungeon is really random, what every appears is just your luck, really.

-Kinds of Drops-

Beyond floor 100, all bosses have different drops compared to their original versions. Every weapon/shield in the game as well as AW Engraved Stones can be received as rare drops in this dungeon. That means that one-time-only quest rewards like Mjolnir and Lambent Light become farmable in the Mugen Dungeon.

But Obviously, because the dungeon is randomized, I don’t know every single new drop for every boss that may appear. I might make a new drop list one day, but the process needed to do that is harder than ever and I don’t have enough time to do that anymore. Sorry.

-Preferred Teams-

You will want to pick teams that are able to cover as many of the buffs as you can while still being efficient at dealing damage. Healers are super important in the Mugen Dungeon so never go into the Dungeon without a Healer (Unless everyone is commuted to healing themselves).

Other than Healers, select characters that can buff all elements and debuffers that can lower the boss’ abilities. The number of players you have present will dictate the kinds of characters you can use in this dungeon. For that reason, I think its compulsory for everyone to level up Liz/Rain, Kirito/Yuuki and Sachi.

You can use any character you want but the ones I mentioned above will have the biggest impact on a Mugen Dungeon team.

One thing I don’t like about the Mugen Dungeon is that using AW characters and some SAO character’s that can’t fly has gotten a lot harder. To be proficient in the dungeon, you need to be able to survive. For that reason, access to healing and overall ease of play becomes valuable attributes.

AW characters were already disadvantaged in normal co-op play but now with they way the Mugen Dungeon is, the co-op endgame kinds of places more emphasis on SAO characters which I don’t approve of.

AW characters in the Mugen Dungeon isn’t impossible, but now it needs more skill and experience than ever and sometimes dying isn’t even your really fault (Especially when fighting the new Super Bosses).  In most cases, Only select AW characters if you 100% sure you are playing with both a competent Buffer and Healer.

I hate to admit it but Oberon is a hell of a character in the Mugen Dungeon. His Royal Torture skill is able to lock down every boss with status ailments so the team can freely deal damage.

He can even do this on Providence and Sacchan but its up to you whether you want to throw your dignity away and use that bastard (>.>)

-Prepare Yourself Now-

Since this dungeon is quite difficult and punishes deaths, teamwork and strong play are needed to be able to progress efficiently. It helps a lot to play cautiously and take absolutely no risks whatsoever.

Don’t fight to win, fight to survive

I think the same logic can apply here. Don’t take unneeded risks and just focus on staying alive. But also, if someone dies, help them out no matter what.

Don’t leave people behind. Also understand that you need one person to go ahead to the next floor so that you can link up with them.
If everyone jumps in the teleporter at the same time, everyone will end up by themselves.

Since English speaking players don’t have this update right now, its a seriously good idea to spend your time building up your characters now.

Also, to those of you saying:

Ah, I’m not farming Rank 10s now. I’ll just wait for Rank 12s.”

You’re going to need a good weapon to get you an opportunity to get Rank 12s in the first place. I’m telling you right now, you won’t get very far with an unupgraded base damage Rank 10 in the Mugen Dungeon.

In any case why don’t you try to experiment with upgrading Rank 10s now to see what the process is like and what kinds of skills you like on weapons.

But that’s it for this post.

Thank you for reading.