For those confused by Marine's Head Exploding
Gorosei & Imu & their Race, are Beings made of Pure Haki
They are "Yokai"
Devils that are inside DFs are actually from this Race
They are Equivalent of Jinn from Islamic Religion and DF Powers are basically OP's Version of Dark Magic
Luffy is basically King Solomon who will conquer all Devils
World of One Piece is created using Haki, it's like a Dream or Matrix-Like World
So these Yokai are basically made of same Energy that created the World, hence why CDs are called "Creators of The World"
And why Skypiea People worshipped such Beings
Every Living Being possesses Haki inside them which allows them to interact with this World
That's why if someone's Haki hits Zero, They Die, which was confirmed by Zoro when using King of Hell Mode
(So while their Lives is presented by their Souls, Haki is like their Key to this Fantasy World)
So the Stronger you are, the Stronger your Haki, and the Stronger your connection to this World
Meaning the key to discover "Everything this World has to offer" is by reaching Highest Haki Level Possible
When Characters unleash their CoC, They are basically forcing surrounding People to feel their entire Haki, and those who are much weaker will lose their sense & get knocked out because they are unable to grasp such High Level of Haki, it's like they get an Error in their heads
In Saturn's Case, He isn't flexing his Haki, He is actually transforming into a Haki Being of very high Level, so those who are Weak cannot see him, hence why that Marine's Head exploded when He looked at Saturn, He was basically trying to access Knowledge in the Matrix that is way above what He can grasp (Worse than a CoC Blast)