Mother Flame power Urunus. Urunus is a gravity control device. We know this from Lulusia.
Enies Lobby is in a constant state of light. An Awakened Light Fruit user caused the hole (think Sakazuki and Kuzan's duel leaving Punk Hazard as a permanently altered climate.
Lulusia, though, is a pitch black crater, that sucks in ships near it. Gravity pushes away light and sucks things into it. So... Urunus functions by using Gravity that operates at a level of Fujitora's Awakening (a permanent gravity field).
The Moon is destroyed because Urunus altered its orbit to change the sea level on earth by altering the tides (the moon control the tides of the earth). This destroyed the Moon's atmosphere, forcing the people who lived their (Lunarians/Shandians) to flee. Lunarians = Moon people. Lunarians have the Mother Flame, because they can absorb the Sun's light, like the Moon, Luna, absorbs the Sun, Sol's, rays of light, and give them to us. Hence, Lunarians.
We see this process when King absorbs Zoro's force; King isn't absorbing Zoro's strength, but his Haki itself, then releasing it via combustion. We know from Skypiea that Seastone is formed from mixing the volcanic particle Pryobloin with Seawater.
The seawater is important because we also know from Moria that salt contains "the essence of the sea" and can be used to remove the Shadows from corpses. So, the salt is "purifying" the corpse of Moria's "Shadows" or "Demons". This is a common theme in general occult works.
So, in order to make Seastone, we need three things: lava (in the right dosage), salt (in the right dosage) and water (in the right dosage).
Since Seastone negates Haki, and is solid rock, the opposite of Seastone would be... a force that creates Haki. This is the Mother Flame.
Seastone binds the minerals in the volcano and saltwater together, and binds them within the circular forces of fire/water. Seastone is more water than flame.
Mother Flame ignites the minerals in the volcano and saltwater together, and releases them through the power of fire. The Mother Flame is more flame than water.
Lunarian's aren't immune to attacks, they can just absorb ridiculous levels of force/Haki, because their skin is made of Seastone, and they are power by the Mother Flame.
King is faster when his flame is off because he's burning the Mother Flame internally and rapidly consuming Haki in order to propel himself at ridiculous speeds. This speed form is powerful as hell, but, leaves him vulnerable.
When the flame is on, King is hardening his body with the Mother Flame in order to avoid attacks. This burns even more Haki, and slows him down, since Seastone is HEAVY AS FUCK. Lunarians are cyborgs built from Seastone and the Mother Flame (Vegapunk is the leading scientist on Seastone, the Seastone on Battleships is why the Sea Kings don't attack them, and the Marines were finally able to enter the Calm Belt after WHO KNOWS how long).
However, this is not a permanent buff, King has to release the energy eventually.
We see this when he just... fucking explodes.
The Mother Flame is more or less Haki in a Can.
"Tired of getting stalled by Rob Lucci? Drink S-Oden, the soda with Oden's Haki in it! Created by the genius Dr. Vegapunk!"
But, don't take my word for it: ask Zoro!
"King almost low diffed me... it's a good thing Hiyori's song awakened Oden's Haki in Enma! Now that I don't have Hiyori to save me, I rely on S-Oden, for that delicious Oden Haki I can't get anywhere else! Rob Lucci is thirsty for blood? Well, Roronoa Zoro is thirsty for S-Oden!"
(This is a joke, Enma taught Zoro how to control his Haki by testing him to meet Oden's level. At some point we'll probably see Enma appear like the Sunny showed up in Film Red as some goofy dude, since the sword clearly has a personality. That's right, we're gonna see these fuckers in the actual manga:
)
The Mother Flame was a gift from nature than people abused to destroy the world.
The Ancient Kingdom used another Machine to create the Redline (a Machine that can create earth/terraform), in order to keep people from drowning, and settled on the Red Line. Eventually, however, they were mostly wiped out.
Imu doesn't have Pluton/Poseidon, Imu only has Urunus, but could no longer use it as he only had one charge left.
This charge was used in God Valley to rescue the Celestial Dragons (mutherfuckers got raptured lol), and then sink the rest of the damn island to the freaking bottom of the world, where Lulusia also is. Hence, God Valley; the place where the Lunarian Rocks murdered Celestial Dragons, and then fell to to the bottom of the world. God Crater might be a more accurate name.
We know from Law that using his Fruit drains his stamina/energy/life span (same with Luffy in Gear 2nd).
This is because Devil Fruit's need Haki to function. Adding two Devil Fruits will usually short-circuit the body's Haki, and... make you blow up, like King. Most Fruits don't take up much energy, but, Law and Luffy's Fruits are just FUCKING RIDICULOUSLY POWERFUL.
Like Deku from My Hero, Luffy was too weak to use Gear 5, because just stretching his body using a Mythical Zoan was heavy work for a kid. It took him awhile to be able to do what he wanted with his Fruit, because it just BURNS through his Haki. That's why Luffy has such ridiculous Haki, his Fruit has been siphoning it to stretch him for years. This is also why Luffy is so ridiculous strong at such a young age compared to other characters (same with Law).
Luffy was always altering reality with the Nika Fruit, he just didn't have the Haki to fight as freely as he wanted to. Now, he has ridiculous fuck you Haki, so Luffy can just... alter reality and shit.
King is a Lunarian with Seastone skin and Mother Flame powers, so his Mother Flame gives him another energy source to route his Haki into.
This also allows Lunarians to eat multiple Devil Fruits. Who have we seen do this?
Teach is a Lunarian. This is why he cries when he looks at the Moon.
To Teach, Lunarians should rule the world, not Imu. Teach believes he is the true king of the world due to his lineage.
This is why Teach was so shocked by S-Hawk.
Vegapunk producing a Lunarian cyborg had this man shitting balls:
Blackbeard joined Whitebeard's crew for the same reason King joined Kaido's:
To hide from the World Government.
You don't have to catch a Lunarian to turn the bounty in.
The WG will pay you 100,000,000 Berry just for giving them legitimate information about one.
Unlike Teach, King is THE GOAT, and refused to betray Kaido even after he wasn't Joy Boy.
Teach, instead, backstabbed his father once he realized Whitebeard was too old to go for Roger's crown.
King has been working with Kaido to revive Pluton (they know where it is if it's under Wano), because Pluton is the Earth Terraforming Ancient Machine, that was used to erect the walls of Wano.
Queen is also, what? A scientist who has been researching King, he was blabbing to Sanji about King's lineage at the end of the fight.
King has been working with Kaido to try to recreate the Lunarian race. By reclaiming the ancient technology, King can revive his people.
Ironically, the "New Force" or "SSG Super Science Group" was literally... yep, the Lunarians.
So, Pluton will be vital to saving lives, because it can create earth.
It's also a GIANT win for Teach, since Pluton is a submarine (see previous posts), and can... terraform land for him, when Teach's entire crew is weak to... water.
Big Brain Blackbeard
Caribou is about to get his own ship, Mermaids, a fucking castle, a fucking Lambo, a yacht, another yacht, a harem or Minks, Caribou is about to be LIVING IT UP.
So, Haki is just light, and Teach has been hiding his true strength because he's a Lunarian. IMO Shanks probably tried to go after Teach in the Time Skip, and had to retreat. The Gorosei (Saturn) also learned from Shanks that Teach is a Lunarian, Teach is the Pirate Shanks wanted to talk about. Shanks didn't want to pick a fight with Whitebeard, but, once Teach left Whitebeard's crew, all bets were off.
Teach without Whitebeard's Fruit would probably lose to Shanks, but, with it, Shanks knew he couldn't.
Rayleigh also knew he couldn't beat Blackbeard because he knows Teach is a Lunarian.
Catarina replies "Ah, so you know about that" to Saturn, because it's the first time the Blackbeard Pirates have confirmed the Gorosei know of Teach's Lunarian Lineage