Luffy and Blackbeard despite being mortal enemies share a common goal of becoming Pirate King.
But what differentiates each of them is how they choose to reach that goal. On one hand we have Luffy who dives head first into most situations (for better or for worse), and makes it through the Grand Line based moslty on sheer willpower and determination. On the other hand we have Blackbeard who takes the complete opposite approach, methodically plotting every step of his journey to becoming Pirate King.
Blackbeard is the narrative foil and speculated Ultimate Big Bad Evil Guy of the story, the true final villain, Luffy’s polar opposite, his dark shadow. Blackbeard is well established as a narrative foil to Luffy, and this even extends as far as preceding Luffy in acquiring power, prestige, and position.
Blackbeard became a new Yonko and a figure of dread and infamy by killing Whitebeard. Whitebeard, who at the time was the World’s Strongest Man and the pirate with the highest known active bounty. The man most feared by the World Government (other than maybe Dragon). However he did it through treachery, waiting for Whitebeard to be old, dying, badly wounded, sick, and exhausted from the Marineford War. He had to desperately call for his blackhearted crew to do the real killing even. Thus, Blackbeard is feared less than the man he killed.
Luffy came after Kaido at the height of his strength. He lost twice already while Kaido has faced down Luffy, Kid, Killer, Law and Zoro all after fighting through the Scabbards, who actually wounded him! Then he fought his own child, Yamato, in an awesome fight!
So Luffy, without wanting to, is also facing a supposedly worn down opponent, yet Kaido hardly seems worn down, tired, or even damaged. We know he is, but he seems to notice it even less than Whitebeard.
Kaido is the World’s Strongest Creature and the now most feared Pirate in the World, with the highest known active bounty. Luffy, also wounded and worn down from previous rounds of this war, now faces him 1v1 again. In the end, even after all Whitebeard endured, he was still too much for Blackbeard alone.
Not so with Luffy. I believe the narrative supports, even demands, Luffy complete this final bout without further help. Luffy will win this fight alone. He has to, in contrast to Blackbeard. Where Blackbeard needed his whole crew to finish off wounded Whitebeard while fresh, Luffy will defeat Kaido without further assistance.
*by Iwasforger03
