So if previously stated that you can permanently control an undead with intelligence lower than 12 the mummy lord fits and also has an animate dead spell for itself. If you control a mummy lord it is counted as a lvl 10 cleric and has • Cantrips (at will): Sacred Flame, Thaumaturgy
• 1st level (4 slots): Command, Guiding Bolt, Shield of Faith
• 2nd level (3 slots): Hold Person, Silence, Spiritual Weapon
• 3rd level (3 slots): Animate Dead, Dispel Magic
• 4th level (3 slots): Divination, Guardian of Faith
• 5th level (2 slots): Contagion, Insect Plague
• 6th level (1 slot): harm
so you could expand your skeleton army a lot more could we not?