In this turn of events luffy suddenly gets a power boost from seeing ace die right in front of him which would devastate him normally, lets see what happens if this was a normal anime where the MC gets a power boost.
As Luffy was about to grab Ace's vivre card from the ground he was unknowingly about to be attacked by akainu (that bastard).
As he was attacked Ace stepped in to stop the attack from hitting luffy.
Everything spilled out, he saw a sight he never wanted to see.
Ace was in front of him with a hole in his chest protecting him from the haki covered magma fist that went straight through Ace's torso .
As Akainu pulled his fist from Aces Chest and began to look at the white beard pirates claiming that they were next after he finished this brat who caused so much trouble.
"N-no, A-Ace, you promised me you wouldn't die" whimpered to his brothers ear
"I'm sorry Luffy, I couldn't keep my promise, you will always be my little brother, even though I carry the blood of a demon, even though many people said I shouldn't have been born… you still loved me because of who I was… tell this to Pops and the others… I can't say it right now… Thank you for loving me!" as Ace said these last words Luffy's mind shattered, his mind was met by the void of darkness, in his subconscious where he was spending some time in the darkness, from the outside world it was 5 min, but to luffy it was an eternity
He just saw his brother die right in front of him, and he couldn't even do anything, he wanted to do more, he wanted to stop being weak, he wanted….. Revenge
Just then he was met by the past user of the Gomu Gomu no mi
"Ohohohoho… looks like you weren't so lucky" the mysterious figure said
"W-Who are you?" Luffy said in a defeated tone.
"Me? I'm a past user of this devil Fruit, my name is JoyBoy!"
"What?"
…
"Tell me kid what's wrong." Joy Boy asked
"I just watched my brother die in my hands, I- I- I- I couldn't do a single thing, Im weak" Luffy said sadly,
JoyBoy's eyebrow lifted, as he suggested the following,
"How about I lend you some of my power, more so my knowledge" he said " i will give you the power to take revenge on those who harm you the most, and allow you to protect the ones you love the most"
"Eh ? you will? I need to kill that lava bastard!"
"Then take my hand and you will receive all my knowledge and power that I have at my disposal."
Luffy quickly grabbed his hand and went back to the real world with so much rage and killing intent it even caught Whitebeard off guard.
Luffy's Hair got longer, he grew to a height of 9'0, and towered above so many people. He started inflating various parts of his body and pumped his blood vessels to the max, and began to look as dangerous as a whitebeard. " gear 5th! Gomu Gomu noooo… Amaterasu" (japanese god of the Sun)
You can Imagine what happens next haha