This feels like the author is trying to do some political intrigue plot... But just not very well as the stakes are just not that big of a deal.
"Oooh, let's try to convince people that the Hero shouldn't have that title."
"What will that let us do?"
"We'll be able to get some political power by controlling the new hero, which we can then use to affect which prince inherits the kingdom."
"Alright, how will you do that?"
"Well, we'll make a big incident that would take real heroics to fix, like a zombie mind control plague thing in a city. So when the Hero fails to do that, we'll have perfect justification."
"But isn't your problem that you wanted to convince people that the actual Hero isn't qualified? That's kind of exactly what she's supposed to be able to do."
"Oh, damnit, you're right. Ok, instead, we'll make a big incident that would take real heroics to fix, like a monster horde invading the city. So when the Hero fails to do that, we'll have perfect justification."
"That's just the same bad idea again."
"Ok, I'll throw a ball, invite the Hero, and bribe everyone to criticize the Hero to her face."
"What will they criticize her about?"
"That she hasn't been able to do anything heroic and is completely failing to live up to her role as a Hero."
"... But won't she have just solved two major monster-related crises that you made? That seems pretty heroic to me. And how do you keep causing monster related incidents by the way? Are you a demon lord?"
Next time...:
"What? No... Of course not... But that's actually a good idea. I'll bribe all of the nobles again and have them start a rumor that she's sleeping with a demon lord. That's definitely not heroic behavior."
"Pfft, who would believe that? You're just throwing your money away."
"What? No... Of course not... Alright, no more bribing. Instead we'll make a big incident where some people try to invade my ball, and it will take real heroics to solve it, except that the whole thing will be solved before the hero even has a chance to move."
"How does that help?"
"This will make everyone start rumors about how the Hero didn't act while a major incident was happening. Confidence in the hero will plummet."
"So your plan is to make such a trivial incident that the hero doesn't even have to move to solve it and the incident is over before anyone learns that there was an incident, and that's supposed to discredit the Hero?"
"When you say it like that it sounds dumb."
"That's because you're an idiot. How do you make sure that incident gets resolved fast enough anyway?"
"So get this, I'll make sure the hero's fiancé solves it..."
wait, i just thought of something. the villainous noble has his "team", right? but did he never even think that Nell might also has her "team"?? the reason his plan was so dumb, was it because he thought he has an army while Nell is always alone???
You've messed with powers beyond your comprehension and your basic comprehension wasn't good to begin with. I'll stage an attack on a party filled with nobles and the king himself, there's no possible way this could go very badly wrong for me.