This quest is to obtain the staff of magi, which is needed to summon the mobs in The British Museum.
Find nimrod in Sumer. He cannot be hunted, so you will need to search all the areas which may require that you do the Epic of Gilgamesh quest first.
Ask nimrod staff
Ask nimrod attune
The magus Nimrod gives you a simple wooden staff.
'Craft the Staff of the Magi' has been added to your journal.
You have to kill the following.
***Note that is says you must be holding the staff, but it works as long as it is in your inventory.
Hold the staff and attune yourself to the earth essence of the Cretan bull. (Greece)
Hold the staff and attune yourself to the fire essence of the dragon Fadhmir in Beowulf (make sure you are FLYING)
Hold the staff and attune yourself to the water essence of a giant sea serpent. (this is the serpent in med south seas)
Hold the staff and attune yourself to the air essence of a fallen Grigori. (mob in seventh heavens, can do solo)
Once you get the staff attuned, return to Nimrod and give him the staff and he will finalize it and return it to you.