Imu used to have fondness on joyboy (in platonic way). Also he might be the last of his kind since he looked different among all the races (and could be a devil with him asking "is there a difference between a god and devil?"). They probably met in the place like skypeia before he become his "first mate", they journey together, meeting everyone around the world until found the devil fruit tree could be in Elbaf or another lost ancient civilization before war starts.
Imu consumed most of the devil fruit inside him before he gained superiority complex that he is able to overpower any powerful races. That is when he and Joyboy clashed together, everyone in their crew him sided with Joyboy while some betrayed him to protect themselves and their people from Imu's wrath. And the reason why Imu was angry at Lili because he thought she was the only one he can call as a "friend" (He called the dragon "traitor").
The One Piece might be the letter from Joyboy left for Imu or the descendants who carried the name of "D".
Skypeia arc was a freaking foreshadow of imu all along! Enel was a sign because of his character design then came along Dressrosa arc, Doflamingo was acting like Imu but in a cheap imitation.
Imu used to have fondness on joyboy (in platonic way). Also he might be the last of his kind since he looked different among all the races (and could be a devil with him asking "is there a difference between a god and devil?"). They probably met in the place like skypeia before he become his "first mate", they journey together, meeting everyone around the world until found the devil fruit tree could be in Elbaf or another lost ancient civilization before war starts.
Imu consumed most of the devil fruit inside him before he gained superiority complex that he is able to overpower any powerful races. That is when he and Joyboy clashed together, everyone in their crew him sided with Joyboy while some betrayed him to protect themselves and their people from Imu's wrath. And the reason why Imu was angry at Lili because he thought she was the only one he can call as a "friend" (He called the dragon "traitor").
The One Piece might be the letter from Joyboy left for Imu or the descendants who carried the name of "D".