It's a bit long, so read it if you like long texts.
"Hm this might be fun, perhaps I can enjoy myself a little after all this time?", amused by the thought of a small challenge Madara decides to taunt Guy.
"I hope you don't end up as a disappointment!"
Ready to accept his fate Guy opens the eight gate without hesitation and rushes towards Madara.
"What will you do huh?", Madara mockingly asked Guy but his arrogance got the better of him as Guy managed to punch him in the stomach without him being able to react in the nick of time.
Guy's punch sends Madara flying several meters away, suddenly Guy appears beneath Madara and delivers a devastating blow to Madaras chin and dislocates his jaw.
"Damn it, I undereatimated him, he's not giving me any oppurtunity to strike back...well then let's see who's going to last longer?", Madara decides to go on his defence and shields himself with his orbs.
However Guy easily manages to kick the Orbs far away from Madara, leaving him completely exposed to Guy's attacks.
Kakashi, Lee, Gaara and Minato are observing the battle but are unable to catch up, only Kakashi is able to follow the fight to some extent thanks to his Sharingan.
"What incredible speed, it's almost like back then...", Kakashi remembers the Chuunin Exams and the fight between Lee and Gaara.
"It's over Madara!", Guy assaults Madara from all sides and sends him even higher towards the Moon.
"Ugh...is that it...?", Madara stares at the Moon as he gets closer and closer to it due to Guys merciless attacks.
"No as if I'd let something so small like that get in my way!", infuriated Madara strikes back with his staff and lands a hit on Guys leg and manages to break it.
Guy stops for a brief second, enough for Madara to attempt another counterattack but that counterattack was meant to fail as Guy manages to send the incoming Orb away with his elbow.
"Neji this is for you, I'll be seeing you soon!", knowing that there's not much time left Guy goes all out and prepares his final attack.
He kicks Madara down to the ground and sends him flying so fast that even Kakashi can't follow up.
Only a few centimeters away from the ground, Guy reveals his most powerful attack.
"Take this...Crescent Eagle!", a Eagle made of Guys aura illuminates the moonlight and flys towards Madara.
Upon impact a huge crater is being formed on the landscape, yet that crater grows in size as Guy delivers one last kick on Madara and breaks his neck.
The fight between Guy and Madara did not pass by the others.
Suigetsu trembles in fear:"What the hell was that, I've had enough of your bullshit I quit!"
Juugo catious as ever finds himself in awe:"This is incredible...is that even possible?"
"So he did open the eight gates...", Orochimaru seems to be the only one to fathom what's going on.
Karin to Kabuto:"Damn it four eyes what's taking so long hurry up already we have to go there!"
"Yeah without me though, that's just suicide!", Suigetsu interrupts.
"Would any of you fools get these damn rods away from me?", Tobirama asked Taka in a threatening yet humorful matter.
At the same time Guy collapses on the ground and has difficulties breathing.
"Guy Sensei!", Lee rushes in Guys direction and takes him to safety.
"Hehe...I did it Kakashi...I win...I'm sorry our rivalry had to end like that my friend...", Guy forces himself to speak.
"No...", Kakashi covers his Sharingan with his forehead protector,"You don't have to worry about that my friend..."
Unable to hold his emotions, Lee breaks down:"Guy Sensei!"
"Lee, it's alright let it all out, I'll be seeing Neji soon...Lee I'm proud of you, make sure to become the strongest Taijutsu user in the world...", Guy sheds a tear and dies with a smile on his face.
The silent roar of Konoha's Beast echoes throughout the battlefield as Guy passes away into the afterlife.
"I can't believe I allowed him to do something like that to me!", shocked by the familiar voice, Kakashi, Lee, Minato and Gaara stare at the crater and see Madara levitating above it and slowly regenerating.