All the enemies are dead except the boss who says he surrenders, what do you do?

[noob]

The deathless in Eberron are (typically) members of the Undying Court.

The spells to create them though are locked behind a setting specific domain, so they might be uncastable in many settings since no deities will have that domain.

Also, deathless are probably one of the worst ideas in Eberron, especially since the setting already supports a grey morality that Undeath not being Evil fits into perfectly fine. But on the topic of draft labor, all deathless are sentient, so that's basically slave labor.

I was not planning on making them work.
They will decide on their own to work(and probably not for me) because doing nothing is boring.
Ex: you animate 50 deathless wizards and they will probably start doing things on their own like a charity business or selling the service of casting spells and so on.