Just as everything finally disappeared, Aku went back to his former form and the sword disappeared back into the ground. Just in time for the royal guards to show up with the princesses and the main six in tow. “Where is Tirek…? Did you send him back to Tartaros? Twilight told us what happened/ Where is the ‘dark world’ she spoke of?” asked Celestia as she looked around, seeing no evidence of any kind of fight. Aku looked back at Twilight before turning his attention to Celestia and her sister “Tirek is dead. That’s all you need to know.”. Celestia’s eyes widen for a moment before she stomps her hoof in disapproval “I said to STOP him, Aku! Not to kill him!”

“Guards, restrain him, and toss him into the dungeon!” Luna barked. “The deal is off! And we will take you prisoner for what you have done…” Just as the guards start to move in on Aku. A sudden round of gunfire carves a line between Aku and the guard as one of the helicopters soars down and ten soldiers drop to the ground with guns drawn. “Back the fuck off before we unload into your asses!” the ranking officer shouted as the clicking of the guns filled the immediate area. Right as when the helicopter landed, Aku was hurried into the helicopter and the soldiers back away with their guns still trained on the guards until they were all inside and the bird took off in the direction of Kazoku. “We got the boss, let's head home.” the pilot said as he went full speed.

“Looks like you were right on the money, sir. They weren’t going to honor the deal like you thought they wouldn’t.”. Aku wasn’t really surprised. This only increased his distrust in this country. And it was going to take a lot more than a little bowing to ever get him to help again. However, he had a new plan. And it is all thanks to an idea he got from his new friend who rested in his pocket.

Wow, just wow!

They CAN'T be f******* serious?! I mean, they DON'T have to deal with Tirek anymore, because he is literally permanently dead. And after everything, this is the f******** "thanks" Aku gets????!!!!!

They are NO BETTER than their evil and racist/xenophobic nobles/subjects. Just let them be at the mercy of another villain that almost wins, next time ( for example: Queen Chrysalis, or the Storm King. ).

And do you know what is the best karma against them? What if some surviving ponies from Tirek's rampage are actually GRATEFUL that Tirek was "permanently gone" ( killed ) in the first place.

And when they learn that their own idiotic princesses were trying to arrest the true hero that not only stop him, but also did the "deed" to permanently get rid of Tirek from ever attacking Pony kind, ever again?

I HOPE there is a F******* angry mob at their castle. And peach Aku as a true hero/leader. And will also denounce the princesses all together for FAILING to stop the villain, once again!!!!

Celestia’s eyes widen for a moment before she stomps her hoof in disapproval “I said to STOP him, Aku! Not to kill him!”

Yep, and as you were begging him for help, that was never going to be anything more than a suggestion for Aku to take under consideration. He considered it. He rejected it. Your precious student is alive. Your precious subjects are safe with their magic intact. Your precious kingdom is still yours. What's the problem?

“Guards, restrain him, and toss him into the dungeon!” Luna barked. “The deal is off! And we will take you prisoner for what you have done…”

Um...what? Not only is Aku not an Equestrian citizen, he's also a leader of his own nation. You can't order his imprisonment because he was only ever on Equestrian land as a favor to you. Calling the deal off doesn't allow you to do anything more than say 'get off our sovereign land and never return', and that was his intent anyway. Is this what amounts to Equestrian diplomacy?

This only increased his distrust in this country. And it was going to take a lot more than a little bowing to ever get him to help again.

...But this implies that there is a way they can get you to meet with them again. Just that it'll be harder. Why are you even considering this? Your nation is already one for refugees. Just ensure that includes Equestrian refugees so that anyone who'd rather throw in their lot with you than the diarchy once this gets out is free to do so. Let's see how long the Elements of Harmony, the Apple Family, and Discord remain Equestria's assets.

Amazing chapter with great detail, keep it up