Hope you enjoy.
Title: Desperate Measures
Cover Story: When is the damn thing going to end already
Luffy's powerful Culverin punch sends Doflamingo flying through the air, and the Shichibukai struggles to right himself.
Doflamingo: No...no, this is impossible! I cannot be taken down now!
Luffy then bounces around Doflamingo in the air.
Luffy: You're finished, Mingo!
Doflamingo: Having to use this is an embarrassment, but this shit has gone on for too long...my ultimate technique...
Luffy: GOMU GOMU NO...
Doflamingo: White Cavalier!
Doflamingo spreads out his arms as strings emerge from all over his body, covering it thickly.
Soon, Doflamingo's entire body is covered in string, with the covering around his head taking the form of a knight's helmet. Now, he is nothing more than a blank killing machine.
Luffy: What the heck? Armor?
Doflamingo: I must admit, Straw Hat, your new form is certainly more versatile than I expected...but did you really think I, Donquixote Doflamingo, am not prepared to counter unexpected techniques?
Luffy: Heh...heh...your armor won't make a difference! Gomu Gomu no Kong Gun!
Luffy pulls in his arm again, and unleashes a powerful blow. However, Doflamingo's counter holds, and he is only pushed a few feet back.
Doflamingo: Fufufu...not so powerful now, I think!
Doflamingo pushes Luffy back, and the two separate a fair distance.
Doflamingo: And despite your increased power...it seems that the form has some drawbacks! Your muscles won't be able to take that bouncing forever...and when they finally succumb, you won't be able to move at all!
Luffy: Crap! He's seen through it!
Luffy then remembers Rayleigh telling something to him.
Rayleigh: I don't have a problem with your new Gear, but don't use it all the time! If you use it too much, your muscles will be unable to move and you'll be a sitting duck for hours on end!
Back to the present
Luffy: So what? I just need to defeat you now! Gomu Gomu no Godzilla Stamp!
In the blink of an eye, Luffy pulls in his leg and shoots it at Doflamingo, kicking him in his armored midsection. The recoil sends Luffy flying back, but Doflamingo is not pushed far back again. However, the Shichibukai realizes with a shock that the string which Luffy kicked has frayed a small bit.
Doflamingo: You're not going to be worn out for very long...so how about I speed up the process! Five Color Spears!
Doflamingo spreads out his arms, and more string begins to pool in his hands. The string wraps thick together, forming five long blades on each hand.
Doflamingo: Spider Web Shot!
Doflamingo spews string from the blades on his right hand straight toward Luffy. Luffy barely manages to avoid it as the string lands on a building and clumps together.
Luffy: If that string hits me...it'll trap me, but I'll keep bouncing! I'll tire out real quickly if that gets me!
Doflamingo: Let's make things easy, Straw Hat!
Luffy: You'll never defeat me like that, Mingo! Gomu Gomu no Carronade!
Luffy pulls both his arms into his body, then releases them Bazooka-style. Doflamingo counters, but...
Doflamingo cries out in pain and shock.
Luffy's blow is so forceful that it manages to fray the string covering Doflamingo's midsection and expose some of Doflamingo's flesh. With great effort, however, the Shichibukai manages to resist the force.
Doflamingo: YOU THINK YOU'RE GREATER THAN ME, STRAW HAT? THIS FARCE HAS GONE ON TOO LONG!
In the blink of an eye, before Luffy can bounce away, Doflamingo slashes him with the blades on his right hand. Doflamingo manages to draw blood this time, and Luffy cries out in pain.
Doflamingo: IT'S OVER!
Doflamingo, with the help of Luffy's bounding force, sends Luffy crashing into one of the buildings. Immediately afterwards, Doflamingo uses Spider Web Shot to bind Luffy. Now Luffy effectively cannot move, but is still bouncing around.
Luffy: Gah...still bouncing...I can't take it...
Doflamingo: Monkey D. Luffy, you turned out to be a better opponent than I would have expected. Still not good enough, however. I'll let you wear yourself out before I come to finish you...in the meantime, I have other fish to fry! Namely Trafalgar Law!
Luffy: I'M YOUR OPPONENT! DON'T YOU HURT TRAFFY, YOU BASTARD!
Doflamingo: Fufufu...relentless as always...after Law is dead, I will finally be in control! I will have the freedom to kill anyone I like just as was promised to me! Starting with the gladiators and all your nakama!
Luffy becomes even more enraged as Doflamingo flies through the air, and he cries out.
Riku: Wait...is that Doflamingo? Why is he flying away?
Usopp: Has Luffy scared him off?
Viola: No...it can't be that...something much more sinister is happening!
Cavendish: Wait...something's flying toward us in the distance...could it be...no, it couldn't!
Law: I'm afraid so...it looks like...we failed.
Doflamingo zips through the air toward the Flower Field. He has a bloodthirsty and demented expression through his helmet. He raises his blades, ready to slaughter
Doflamingo: And now...EVERYTHING BECOMES THE WAY IT WAS MEANT TO BE! THE HEART'S LEGACY...WILL BE ERADICATED!
Luffy: Huh...huh...I'm getting weaker...but I need to stop Mingo! I HAVE TO! COME ON! AAAAAAAAAAAAAAAHHHHH!
Cavendish: I promised Luffy I'd protect you, Trafalgar Law...and I fully intend on keeping my promise! I may die here...but my heroic actions will make you and all the other Supernovas remember me forever!
Law: I also made a promise to Luffy, Cavendish! This was my fight from the beginning! I must also die alongside Luffy!
However, Doflamingo and Law are stopped in their tracks when Luffy appears between them in the blink of an eye.
Doflamingo: What...how? No one can break through my string mass!
Luffy: My nakama and everyone else on this island are suffering because of you, Mingo! I'll never let you hurt them again, and NOTHING WILL STOP ME! NOT YOU, NOT YOUR HENCHMAN, NOT EVEN ME!
Luffy pulls his arms back into his body again, but even deeper this time. They are pulled so far back even his shoulder blades are pushed back.
Luffy unleashes rapid-fire punches Gatling Gun-style, and these go so fast that it is hard to even see them. Doflamingo does his best to counter. He raises his arms, covering his already-hard armor in Busoshoku Haki.
It's still not enough.
Quickly and surely, Luffy's rapid punches wear away at Doflamingo's armor, until it comes apart, leaving the Shichibukai's midsection completely exposed.
Doflamingo: No...! I can't-!
Luffy hits Doflamingo's midsection with both of his fists in one final, ultimate blow. Time seems to be slowed as Doflamingo floats back, coughing up blood. Time then returns to normal as Doflamingo is sent flying at an incredibly high speed, up toward the Birdcage.
Doflamingo: No...going too fast...can't stop...
The citizens of Dressrosa stare in shock as they see their king flying through the air. Doflamingo continues flying, the force of Luffy's punches too great for anyone to shake off. For once, he had no way to counter. And so, Donquixote Doflamingo met his fate at the hands of the weapon he had created to kill everyone else. Everyone but him. After receiving his due number of cuts, the force of gravity finally takes effect on Doflamingo, and he goes down.
Doflamingo: No...this can't be...the way it ends!
Doflamingo makes a hard landing on his back in the center of the King's Plateau. He coughs up blood, but otherwise does not move. Luffy bounds up to the King's Plateau, huffing and puffing.
Luffy: You're finished, Mingo!
Doflamingo: Haaah...I will admit, you've completely immobilized me, Straw Hat...but...MY NAME IS DONQUIXOTE DOFLAMINGO! I AM HEAVEN'S CHOSEN! AND NOW, IF I FALL, THE WORLD FALLS WITH ME! FUFUFUFUFUFUFUFUFUFUFUFUFUUUUU!
Doflamingo continues laughting maniacally, at an increased rate. Meanwhile, the Birdcage remains standing, but something about it appears to be changing...and it's not looking good...