Create Greater Undead

Your mastery of what causes the undead to rise allows you access to more powerful servants. Chose up to 10 corpses of creature that are large size or smaller, over the course of an hour you raise them as undead that fit the size of the corpses and are below cr 10 undead.

These undead will obey you for up to 72hrs before you must cast the spell again to reassert dominion over them. After four uses of the spell to do this the undead serve no other but you unless you die or leave the plane you currently reside in. Then you must do the process again.

At Higher Levels: casting this spell at ninth level allow you to raise the cr restrictions up to cr 20 undead