To get Rainbow Haki in Blox Fruits, first, ensure you’ve reached level 1950. This is crucial to unlock the quest. Next, head to Floating Turtle Island and find the tallest tree where the Horned Man resides. Engage with him to start your journey.
The Horned Man will task you with defeating five bosses. Begin with Stone on Starter Island. Once he’s defeated, return to the Horned Man to receive your next target. This method keeps the process smooth and frustration-free.
Next, take down Captain Elephant near the Mansion on Floating Turtle Island. Then, head to the Giant Tree to defeat Kilo Admiral. Continue your quest by defeating the Island Empress on Hydra Island, followed by the Beautiful Pirate inside the Beautiful Pirate Domain on the same island.
After defeating each boss, always return to the Horned Man for the next target. Once all five bosses are defeated, return to him one last time. He will reward you with the coveted Rainbow Haki. Enjoy your new power!