Two Greater Stigma slots have been added in the 2.0 update. The quests to unlock them become available at Lv 52 and Lv 55.
 
While the Lv 52 quest is not very difficult, the Lv 55 quest requires a total of 14 quests with a high level of difficulty due to many of them being located in the Beshmundir Temple, the most challenging instance in Aion to date.

This quest can be started when a player reaches Lv 52. For this quest, players much retrieve the quest item from the solo Instanced Dungeon, Taloc’s Hollow. The difficulty is rather low, but players will need to enter Taloc’s Hollow twice. Since you will not need a group to complete this quest and it unlocks an additional Stigma slot, it is beneficial to complete it as soon as possible.

The Lv 55 Stigma Quest starts with Supplies Party and contains a total of ten main quests and four sub-quests. The main stage for these is the Beshmundir Temple Instanced Dungeon, and the entry requirements are complicated. It’s best to complete the entry requirements early so you don’t miss an opportunity to enter Beshumundir Temple when it is available.
 
There are many objectives to complete inside Beshmundir Temple. It is a good idea to build a trustworthy group of other players who are committed to reaching the same goals. That way, you can complete numerous objectives at once and spend as little time as possible on unnecessary endeavors.

The quest line begins with “Supplies Party”, and can be accepted at Lv 55. The entire quest line consists of 10 quests up until “Stigmas and Scars.” Among these, the last quest, “Stigmas and Scars,” requires two quest items. In order to acquire the quest items, you will need to clear the four sub-quests detailed below.

Quests:

These quests are obtained inside the Beshmundir Temple instance.
They can be accepted during the “Stigmas and Scars” quest and the two required quest items are given as rewards. With these, players can complete the “Stigmas and Scars” quest and unlock their 5th Greater Stigma slot.