Oracle Dungeon

Once you reach base level 60, Oracle Dungeon is unlocked from the instance menu.  

This is a weekly group instance that pits you against several mobs, traps, and bosses in an arena.  This dungeon has Two difficulty settings (Normal or Elite), each with Twelve stages.  Completing a stage gives you the rewards from all the stages beforehand so aim to complete stage ten to get all your rewards in one run.

You may use your Lucky Coins on this dungeon to receive extra loot at the end though you will not receive extra Nolan Cards.

You may enter Oracle Dungeon by heading to the area below in Prontera or by opening the Instance interface from the More menu.

There are two NPC's here of interest.  The first, Helge (shown on the right here) will let you see the deck for each difficulty.  The other NPC, Harrod, will allow you to enter the dungeon.  When challenging Nightmare make sure to talk to Helge first and review bosses to determine if your group has to do anything special, for example opening a chat room when Loli Ruri spawns.  Be sure to discuss with you group beforehand so you know what to do.

This dungeon was updated in this last patch and now offers 13 stages, each with a normal and elite version.  Higher difficulties reward more Nolan cards and card albums are now character bound as opposed to being sold on the exchange.  You can still open them and sell the cards that come out on the exchange though.

You can also use the + sign at the bottom where it says "Reward Count" to unlock up to three additional runs for the week but according to the helper text you will not receive Nolan cards for this.  You can "raid" (instant clear) these three additional runs but it's probably not worth it if you don't get Nolan cards.

If you complete stage 13 on Elite you will earn 1140 Nolan Cards per week

When you enter the dungeon the deck is shuffled so be sure to speak to the NPC Sigmond in this room and select the View Card option to see the order the deck was shuffled in.  This will let you know when to expect things and if you notice something unfavorable the group can leave and re-enter to shuffle the deck again.  When everyone is ready the leader clicks Start and the fun begins!

Your goal here is to draw all 60 cards in the deck and defeat all the monsters.  Every 25-30 seconds the next 3 cards shown on the right side of the screen will be drawn at once.  There is no way to speed this up or slow it down so if your group cant kill quick enough you may get overwhelmed since the mobs do not despawn when no ones show up.  This means you need to survive for around 10 minutes.

Several cards are trap cards that cause deadly effects such as meteor fall which drops meteors all around the map that will easily one shot you.  I've included some examples of deadly traps below.

Once the entire deck is drawn some time will pass until the outside of the circle fills with green acid.  This will kill you extremely fast so when the deck runs out everyone should run to the middle of the room and kill the boss as quickly as possible.  Though I've never seen it, it's entirely possible that the whole room will fill and wipe your group if you don't kill it in time.