You will need an Oren Sewer Key before you start this quest.
Head to Oren Island City and enter the Oren Sewers Entrance at (56,128).
Go down the stairs and your Oren Sewer Key will be consumed and you will receive the Legend Mark "Explorer of Oren Sewers". This will grant you permanent access to the Sewers.
(Map of Oren Sewers)
Head to Oren Sewers 4 and enter the portal at (32,5).
You will be teleported to Oren Sewers 5.
Make your way to Oren Sewers 9.
Each group member must kill 2 Salaman Guard.
Note: You must deal the final blow for the kills to count.
Enter the portal at (20,18) once all the group has their kills.
You will be teleported to Oren Sewers 14.
Head to Oren Sewers 15.
Each group member must kill a Pirate Guard.
Enter Oren Sewers 16 once all the group has their kill.
Walk towards the back of the room and speak to the Fountain at (12,11).
You will receive 850 Health and 850 Mana.
This quest can be repeated every 6 months.