The concept of a graveyard was mostly relegated to human needs for a place to pay respect to the dead or a place to honor the dead. It also was usually limited to powerful clans or powers to only bury the known dead under the auspice of glorifying their lives for all eternity.
Tombs existed for those that grew powerful enough to leave a pseudo Inheritance behind as well. It was usually a simple test for descendants compared to the general admittance to an Inheritance.
Yet, all those were human things. Demons may leave a marker for an ancestor or perhaps forge a weapon with the bones of the same but a graveyard was a foreign concept to them.
Tombs were not impossible but they were usually a simple life and death trial for the worthy to face or claim a powerful artifact/weapon.
