Ludibrium Party Quest
You need to be at Level 35-50 to do the party quest
Head to Ludibrium: Eos Tower 101st Floor and form a party of 6 members.
Note: Your party needs to include a Magician with Teleport, a Bandit or Assassin with Dark Sight, and an Assassin with maxed Keen Eyes or a Crossbowman with maxed Eye of the Amazon. A Cleric is highly recommended. All-Cure potions are also highly recommended, as the battle with Alishar will occasionally leave your skills locked or your character being inflicted with the darkness effect.
Have your party leader click on Red Sign.