Luffy’s fist looked much smaller compared to Kaido in Chapter 1048 than it did in Chapter 1047.
I thought Oda might’ve nerfed the size of it a bit, but nope. If you look closely, the real Kaido is inside his new form Kaen Daiko.
Kaido breathes a large amount of flames from his mouth, forming a giant fire dragon over his original dragon body.
The heat of his fire dragon near-instantly melts everything that it comes into contact with, preventing opponents from touching him.
See how Luffy’s arm is still connecting to Kaido’s head? You can follow the arm up to a black patch… that is actually Kaido’s real head!