If Maki exists, and Imu uses it to protect Himself, it means it is a different form of haki use, it seems to go in every directions too, Not only focused on Himself only.
Could maki be a form of "weakened" or old Haki you know.. something that was trapped for too long inside Imu's body After he died ??
Or, Maki is something Related to his fruit, his power of the Devil.
Like, Imu seems to control some Kind of Haki too, because he was able to transfer and transmute his own dark energy INTO the weapons and the 20 swords of the World Government... And, is also able to provide power to the HKs..
So, either it might be a corrupted energy or a specific type of mastered Haki..
and, his defensive skills in GValley proved me wrong about the Ancient generations.
Some Kind of Armor is protecting his Body during his fights.. before he runs out of gas.
I am sure he finally will show Off some Haki fighting skills of some Kind aside from his transformations.
And, something triggered me when Imu said that "Joyboy was killed long time Ago..." Could that mean that he was the previous Joyboy or the original One from the first World ?? And, later on he created the Devil fruits After he died as a Memory of his own World ??
To Die, Imu will need to pass down a Knowledge of the Ancient World maybe ??