Not all of Rathma’s teachings are imparted to neophyte Necromancers. Some of the more powerful, darker secrets are only divested to those who have proven themselves worthy. You’ll start out with access to Skeletal Warriors and as your power grows you’ll be able to add Skeletal Mages to your warband, but a much more powerful minion can be created by the most powerful of Necromancers. This page will cover the Necromancer-exclusive side quest Call of the Underworld in Diablo 4.
How to Start Call of the Underworld in Diablo 4
No amount of searching will help you find this quest. You must get your Necromancer to level 25, after which it’ll become available. Once done, you need to make your way to a Shrine of Rathma found northwest of Menestad, along the northwestern edge of Sarkova Pass. Make your way there and interact with the shrine - no living Necromancers may be nearby to help you develop your powers, but for beings to regularly deal with the dead, such a barrier is hardly a bother. A shade name Maltorius will appear after you pay your respects at the Shrine of Rathma, and he’s all too happy to help you out.
Harvest 12 Unbroken Bones
Your first task is to acquire some raw materials in the form of unbroken bones. Fortunately, some Bone Warriors will appear, allowing you to destroy them and harvest the bones you need from their remains. Go around destroying undead and pick up the Unbroken Bones they drop until you have a dozen - you need not go far, a blue search area marks out the narrow confines of this task.
Return to Maltorius with the twelve Unbroken Bones and he’ll give you your next task - bones are all well and good, but without any animating spirit, all you have is a macabre pile of remains. You need to head to a nearby dungeon which houses a “vile artifact” that traps lost souls - free these souls and they may just decide to help you out…
How to Fill the Jar of Souls
To find the Bitter Cave - where this “vile artifact” is being house - you’ll need to travel south. Once you enter the cave, you’ll find that this dungeon doesn’t have much to offer save for the objective itself - the Jar of Souls you seek is the only other object of note, and there’s no opposition standing in your way.
Find the Jar of Souls and interact with it, at which point it’ll start to spew out souls, which possess nearby Skeletons. Smash the skeletons to fill the Jar of Souls and… wait, are we freeing these souls from the jar, or putting them back in it? Whatever, kill enough to fill the Jar and you’ll get your Golem shortly thereafter. Note that you can modify the exact type of Golem you have and its abilities via the Book of the Dead. You’ll also need to equip it as a skill to make use of it.
How to Get a Golem in Diablo 4
Once your Necromancer reaches Lv25 in Diablo 4, you'll get the quest "Necromancer: Call of the Underworld". Find a Shrine to Rathma along the norhtwestern edge of Sarkova Pass, where a shade name Maltorius will instruct you to collect Unbroken Bones before tasking you with freeing some trapped souls. Follow Maltorius's instructions and you'll end up with your very own Golem!