Lich (or other undead mastermind) commanding a genuine horde of the undead

[Segev]

One of the iconic designs of a necromancer bad guy is to command a genuine unending horde of shambling corpses. However, in D&D, there are limits to this. Means do exist to have chains of authority - control a wight, and have it order its spawn to obey you - but you have to be careful not to let that wight die.

Spellstitch your undead minions, however, and you can create more chains: animate dead from your controlled minions is potent (though getting a mindless undead with the requisite Wisdom is tricky). Intelligent undead are harder to control, especially for the arcane caster who lacks Rebuke/Command class features.

But there's a way to gain more direct control. It's an inversion of what one might expect, and it requires the master necromancer to be undead: undead lieutenant. It's a 3rd level sor/wiz spell which allows the caster to grant control of his undead minions to another undead of Int 5 or higher. Spellstitch it into your minions who can create spawn or otherwise gain control of undead they create (such as also being Spellstitched with animate dead). Have them use it on you.

Yes, "obey him as you would me" works, too, but this spell ensures that the control lasts for the rest of the day even if some mishap occurs to your chain-of-command minion.

This is particularly useful because ghouls are capable of being spellstitched with undead lieutenant, and (with a cleric's help) animate dead. And you can create ghouls which are under your own animate dead cap through the spell ghoul gauntlet.

(It's a bit weird that ghoul gauntlet is the only way to get non-skeletons/zombies under that control cap, as well as for an arcane necromancer to control intelligent undead for more than a minute/level. They can 'charm' them with command undead, but that's not going to compel them the way that is so iconic to necromasters.)

[g3taso]

That is an excellent suggestion, and it works!
Note: Our campaign uses PF and 3.5 material.

As one way of doing things Bubba, the Undead King of the South gets a hold of a simulacrum of a Dread Spectre or other incorporeal critter and casts Ghostbane Dirge (PF spell) as a persistent spell on himself long enough to spellstitch it with Undead Lieutenant (and maybe Ghost Trap) in addition to others. This critter creates a variety of spectres out of village commoners and such. So now Bubba has control of the simulacrum directly, and with Undead Lieutenant also controls his little helpers.

Together the simulacrum and spawn begin taking out outsiders that Bubba thoughtfully summons into a stocked kill room (obviously, the minions are instructed to weaken but not kill the outsider, that is the simulacrum's job). These are the "real" minions we want, not the weaker simulacrum or his low-HD minions we acquired for the sole purpose of "preparing" outsiders. These outsiders are up to 18HD with lots of spiffy abilities and now with Undead Lieutenant I directly control them as well. In this example, Bubba "acquires" a half-dozen Valkyries or other pretty-spiffy outsiders and brings them into the fold.