I just finished the Pong Krell arc on Umbara, and Krell spoke of becoming apart of the New Order. If a Jedi had turned Dark as Krell due to a force vision or another reason, would Sidious have accepted and let the Jedi serve prior to his formation of the Inquisitors? I am not speaking of him raising and training force sensitives, but fully trained Dark Jedi like Krell or Asajj serving in the Empire during last days of the Clone wars.
Or would Sidious always be suspicious of them?
__________________ "Happiness is a lie. Life is horror. The light is always dying all across the universe. The last star will flicker out someday, when it does, all that remains is shadow. And I will be its king!"'-Amahl Farouk
He'd use them, not any different then when Jerec or Cronal were around really. If he deemed them threats, he'd either move them(as he did Cronal) or cut them off from knowledge(Jerec) or perhaps just eliminate them, but probably the former as he'd have uses for them and by that time they most likely would have to follow or be destroyed.
Eh I think them just being Dark Jedi is better than sacrificing them, that's probably the worst thing for the Jedi to cope with that they now have to fight against a former friend. Hanging it over there heads and all that, killing them wouldn't have that impact much.