He had just transmigrated into the body of Portgas D. Ace, the Fire Fist, when Admiral Akainu punched straight through his chest! The anguished cries of his younger brother Luffy awaken the proud, solitary soul from the Fighting Game Capital: Iori Yagami!
“Such a troublesome guy!” Ace’s final wish becomes a shackle binding Iori to protect Luffy, leaving him no choice.
When Akainu throws another punch, Ace’s Mera Mera no Mi is completely devoured by an even more terrifying purple flame!
[Oniyaki] shatters magma, [Yami Barai] annihilates justice! Against Admiral Kizaru, he even blasts him apart on the spot with [Ura 1211 Shiki: Ya Otome]!
“An admiral? Too weak.”
“Blackbeard? Just a damned traitor.”
“This world only needs to witness my existence! Cry, scream, and then die! The name Yagami will become the nightmare of everyone in the New World!”
I've read more than a dozen chapters and it's pretty good.