Undead Lieutenant

You imbue one undead creature that you control with an enhanced sentience and, if required, the ability to speak one language of your choice, such that you can delegate some degree of command to it. When you cast this spell, you may explain an objective or set of objectives for the lieutenant to achieve. These may be as abstract and complex as you wish, and the spell's power compels the target to understand your orders. You also designate up to 4 other undead creatures that you control. Those creatures then remain under the command of the lieutenant for the duration of the spell (even if your own control over them would expire within that time).
     On each of its turns thereafter, the lieutenant can use a bonus action to mentally command any of its subordinates, as long as they are within 60 feet of it - it will use this ability whenever it can in pursuance of the objective(s) you set. It can command any or all of them at the same time, issuing the same command to each one. If it issues no commands (such as if it is incapacitated or out of range), the subordinates only defend themselves against hostile creatures. Once given an order, a creature continues to follow it until its task is complete.

At Higher Levels: When you cast this spell using a spell slot of 4th level or higher, the duration becomes 8 hours and when you cast this spell using a spell slot of 6th level or higher, the duration becomes 24 hours.

source: mfov.magehandpress.com/2017/02/necromancy-spells.html