And I can pretty much see that he would try to Disable Fate, paralyzing him, but Fate could potentially control Dusknoirs mind to make him do what Fate commands him to do, but Im not sure if thats combat applicable.
I'm assuming Fate doesn't use his mind control in combat, so Dusknoir via using one of his orbs, which have the effects of one of sleep manip, paralysis inducement and/or power nullification, fear manipulation or transmutation, along with a few others. The AP feat he scales to is very casual (Primal Dialga controls a timeline with its heartbeat) and Dusknoir has at least one reviver seed to resurrect at least once.
Well, according to the profile, all he did was give a sinful man a change of thought making him look over what he did wrong, causing him to beg for forgiveness, but Dusknoir is rather a redeemed character, so I am pretty sure he would not be affected.
Like I said, Dark Dragon’s abilities mostly depends on the users heart and desires. Concept manip comes from the fact that Lucas wished away the concept of evil. Had the Masked man fulfilled his duty of pulling the last needle, The Dragon would end up erasing The Universe, including itself.
As for Ness, yeah it’s no surprise. Other than the fact that he lost probability Manipulation, but it’s no issue for him.