Against its nature?

[Nail]

Ordering a Paladin to fight his allies is fine.

Not IMC.

Fighting your friends (and Dominate Person does NOT remove your former friendships) is against the nature of any Good creature, and arguably any neutral or lawful creature as well.

 

[Nail]

What I wanted to do was force the subject of the dominate to come under the affect of the mind fog, and then I can order it to preform an action against its nature. That way the dominated person will have a small chance to succeed on his second will save.

Nice try.

Voluntarily failing a save that has an effect that is not (harmless) is against the nature of any creature.