Omaren guardians

There are seven special guardians that protects Delera's Tomb in the quest The Missing Party. Each of them wards an optional individually (Around 500 XP each), and if you kill them all, you get another optional (around 1400 XP). Two of them spawn on your normal way of completing the quest, but are not required kills.

South of the first shrine, with a help of your party, or some very clever tricks involving an hireling, you can access a secret room crossing the underwater passage that is home of Omaren Assassin, Omaren Pugilist and Omaren Executioner.

On the big room in the east, Omaren Sniper will appear near the coffins. Defeating him will open the way to a trapped chest. You can't disarm those traps.

South of Omaren Sniper you will find a locked door. Pick it and you will find Omaren Magus halfway on the corridor, and Omaren Ecclesiast at the final room.

Across the last shrine you can find a secret door. Behind it, will be waiting Omaren Slayer.