Oda likes to use filler material for foreshadowings. Luffy also has horns here which further demonstrates he had this vision of making Luffy into a giant versus Kaido.
Maybe we should pay closer attention to fillers for foreshadowings and even powerscaling because Oda seems to be involved in fillers
Maybe we should pay closer attention to fillers for foreshadowings and even powerscaling because Oda seems to be involved in fillers