The robot "Iron Giant" is one of the main characters in the ongoing Egghead arc. It has been hinted several times that it may come back to life and fight alongside Luffy in his Gear 5 form, aka Nika. Finally, the ancient robot came to save the day and averted Gorosei's fury. Therefore, if you are curious about the existence of the Iron Giant robot, here is everything you need to know about it.
Who is the Iron Giant Robot in one APRON!
About 900 years ago, during the Void Century, the Iron Giant, also known as the Ancient Giant Robot, was invented. We still don't know why this giant robot was invented in the first place. The energy used by this robot to function is produced by listening to the Drums of Liberation that play when Luffy enters his Gear 5 form. But there was also an ancient energy used to power this giant robot.
The iron giant ran out of energy after the Mary Geoise incident about 200 years ago and went into hibernation. The World Government had ordered its destruction, but the scientists decided to study it instead. So in the end, Dr. Vegapunk bought the Iron Giant and kept it on Egghead Island.
After hearing the Drums of Liberation beat as Luffy entered his Gear 5 Nika form on Egghead Island, the robot restarted and began helping the Straw Hat Pirates fend off the wrath of the Five Elders. Also, in One Piece manga chapter 1119, Iron Giant Robot's name was revealed as "Emet."
