4 actions: Fanatical Frenzy Jr. Edition: Legend speaks of a great and fanatical space empire, which wielded a powerful weapon of mass... no not destruction, for very few things actually get destroyed by it. Mass evangelism might be more accurate, though calling it that massively undersells its true power. When fired, this weapon instantly infiltrated the minds of every last sapient being on exactly one planet, and re-wrote their thoughts to utterly adore the deity of the empire that had this weapon. This would drive the people into a zealotry so strong that they would all collectively and immediately, from the lowest laborer or crook to the highest robber-baron and official, rise in revolt against their home civilization and raise the banner of the fanatical empire on the spot. This weapon in it's full form is (thankfully) lost to time, however I have recovered part of it's technology and created a much weaker version.
Using direct mind control is morally questionable, but no-one will know. And frankly, this is very necessary. I've attached a cloaking device to the weapon's projectile, nobody notices it as it flies over to the Holdouts, currently debating the merits of the Godmodder. The weapon activates, and suddenly the Holdout protoss stop caring so much for the Godmodder. The image of him in their minds goes cloudy, a vague thing rather than something glorious to follow. Then they begin to feel disgust for the Godmodder, wondering why they ever followed him. The thing that takes the Godmodder's place in their minds as something to live and strive for is not a physical person, but an abstract ideal: that of peace and tranquility. Non-violence becomes what they want above all.
And of course they need no extra mind control to know that peace is something the Godmodder will never give them, except perhaps in the form of desolation.
Are you sure this won't backfire? Very, very sure?