Just imagine following scene:
Luffy told his crew and alliances he has to deal with something (about Tama f.e.) and promised he will be back at the fight at the firefestival. While he was at Tama, Luffy got captured by Kaido and imprisoned at a cave on Onigashima. There he got chained with Seastone-Chains, like DoFlamingo got on the Marine-Ship. They weaker him extremely, that much, it isn’t even possible to hold his head straight up. In front of him, he sees some transponder-snails, not knowing what their meaning is.
When the Firefestival begins, the crew and alliances arrive at Onigashima, where Kaido already waited, because he knew they would come. The war begins and takes about a week full of fights, while Kaido was just eating and watching. In this week of fights, most of the Kaido-Crew gets defeated, so Zoro was able to deal with King, Sanji with Queen and so on. After that weeks, everyone is extremely exhausted and still wondered where Luffy is, some assumed him to be dead and lost their morality already. At the end, just the Crew strands straight in front of Kaido, missing their captain. Kaido stands up and walks to them. When Kaido looks down at Zoro, which obviously don’t fear Kaido, doesn’t move a cm, he starts to swing his club to hit Zoro. Zoro just stays there, not moving, but starts to speak:
“It doesn’t matter if you kill me, or the rest of the crew, or even the whole country… at the end of this war, you will be defeated by Luffy, the King of Pirates.”
Luffy is listening to these words through the transponder-snails which are placed in front of him. He listened to the whole week, through the screams, the wins, the looses and now Zoros. But before he could take a smile from this honor, he hears the sound of Zoros Body get hit by the club and being smashed to the ground, together with his swords. Luffy flinches and starts crying silently, when he hears that the next one gets smashed, Sanji. Then Usoppe, then Franky, then Brook, Robin, Chopper… Luffy is crawling, crying, screaming, full of despair and hate, every time one gets hit, he flinches and screams, like he was getting hit instead of the crewmate, but still, he is unable to move or even escape. Kaido uses the situation to break Luffy and make him his.
Then, Kaido goes for the last Strawhat, Nami. He went for hitting her, but Tama jumps in front. Confused for a second, Kaido stops. Tama declares to him: “If you don’t stop right now, big bro Ace will come and safe Wano from you!”
Kaido response: “Your Ace died 2 years ago, like your friends will die now.” After these words he just slaps Tama away, now aiming for Nami.
Luffy, listening to these words, just heavily breathes and whispers… “ace…”
Nami see Tama get slapped and falls on her knees. She has all her friends in front of her, laying down, bleeding, unconscious. Tears are all over her face, she just feels a deep helplessness and despair. When Kaido starts to swing his club, Nami just crys all over and starts screaming: “LUFFFYYYYYYYYYY…”
Right in that moment, at the other side of Onigashima, a huge explosion comes up. An explosion without fire, but with pure Haoshoku Haki, so strong, seastone-chains from that place was thrown directly in front of Kaido. Above the explosion, the sky got split, the weather changed and the whole place seems to be destroyed. While Kaido is confused and angry at the same moment, he is silently looking at that place, when a wave went through the sky, through the air and through the ground… a wave of a scream, Luffys scream:
“KAIDOOOOOO!”
