Criteria

Doflamingo wants to stand up but he realizes that he is being pinned down by the feet of a young girl, he can't move it at all, he feels trapped by a heavy boulder.

He grab Astrea's legs and tried to push them away but he felt weakened after grabbing it. His strength is benign.

What he doesn't know is that all the Angeliod is already redesigned and re-equip the most modern and advanced technology to counter Devil Fruit Users.

It was stated that Seastone "gives off a wavelength that is the same as the sea itself" and referred to it as the sea in solid form. It is also said to be as hard as a diamond.

Because Seastone so strongly resembles the sea itself, Sea Kings cannot perceive it. By layering the bottom of ships with Seastone, creatures that are underneath the ship will be unaware of the vessel's presence, and thus will not attack it.

However, while the Seastone hides the movements of the vessel while it is traversing above the Sea Kings, that does not mean they cannot see the ship; if a Sea King comes to the water's surface, then it will be able to perceive the part of the ship that isn't protected by Seastone.

Upon contact with a Devil Fruit user, Seastone will drain the Devil Fruit user of their stamina and nullify their powers.

Coming into contact with Seastone has the same effect on a Devil Fruit user as if they fell into the sea, minus the risk of drowning.

This weakening effect only works upon direct and constant physical contact with the Devil Fruit user in question, the effect stops immediately once the Devil Fruit user is no longer in contact with the substance.

Seastone can be modified to make a Devil Fruit user weak to only a certain extent; for example, Seastone handcuffs are generally modified to rob a prisoner of their powers, but still leave the prisoner strong enough to walk normally, and in some cases, perform hard labor.

The degree of "weakness" induced by the Seastone depends on its density and composition, 100% pure Seastone having the greatest weakening effect on Devil Fruit users.

Although, a Devil Fruit user can resist and even ignore the weakening effect if they have enough physical endurance.

And right now, each Angeloid has extracted the property of Seastone, not only they can be detected by giant Sea Kings of the sea, but they are also exclusively the nemesis of every Devil Fruit User.

The Addition of the hardness of the Sea Stone makes their skin hard as diamond, strong as steel, and flexible like rubber.

With Sea Stone, being unable to use Haki is now not an option plus Xin's personal Magic that adds power and defence to Ikaros and Astrea, they are now a certified being to recognize.

"Can you remove your feet, woman?"

Astrea looked at Xin for confirmation and seeing Xin nod, she was reluctant to move his feet and walk behind Xin.

Doflamingo removes the dust from his pink feather coat but this time he is just silently listening but everyone knows that he is angry right now.

"Jejejeje we meet again kid, i didn't expect you to be that Legendary Guild Master." Marshall D. Teach look at Xin, with a friendly tone.

He is not idiot enough to pick a fight that he can't even win, he looks like an idiot but actually, he is smarter than any of them.

"Yeah, Big Man Pancake, I did not expect to see you here that fast, I thought you would need a year to step here." Xin said while calmly sipping his tea.

"Well, I'm just lucky enough to grab a pretty good prey so I handed it to him and became Shichibukai after learning there's a vacant seat."

Well, actually there's no criteria which is mentioned or shown in the anime that is required to be a Shichibukai (Warlord) or a Yonko (Emperor) in One Piece.

First of all, the Warlords are seven powerful and notorious pirates who have allied themselves with the World Government.

Any notorious pirate who is considered a threat by the World Government can be invited for the post.

In Xin opinion, any pirate with a bounty of 80 million berries or above and who is considered a threat by the World Government is eligible to become a Warlord. Someone like Blackbeard, who can hand over a dangerous pirate like Ace to the World Government, also seems eligible for the post.

After all, Blackbeard shows a huge potential after becoming a crew of Whitebeard Pirates, escaping after berating them and catching the 2nd in command Ace.

The special requirement of the Marine is actually just an empty baseline that they created to fool everyone.

Just becoming a Pirate with an 80 million up bounty, a huge potential to become a powerhouse is already enough to become Shichibukai.

The Yonko are the four most notorious and most powerful pirate captains in the world, but are neither allies nor enemies of one another, preferring to remain autonomous under most circumstances.

These four individually reside within the second half of the Grand Line also known as the "New World", exerting impressive influence and control over dozens of other pirate crews and self-governing islands.

Now, in the case of Yonko, one needs to be among the strongest pirates and have many fleets under his possession.

A Yonko generally has a very large territory under his control. The bounties of Yonkos are kept secret so, I guess it should be at least above 500 million berries and could possibly be over 1000 million berries.

But still being strong enough to be recognised by everyone and the currency Yonko itself is the criteria for being Yonko.

"You're lucky, tehr still no bounty for you or else you are already sitting with Ace on the lowest level of Impel Down."

"Thas no going to happen, I'm already a Shichibukai, you can't touch me or else the World Government wil into let you go."

"Kukuku~ World Government? This kid is already fighting the World Government so you don't for a couple of months so you don't need to use the World Government as a shield." Doflamingo informs them.

"Your pretty brave Young Master Xin, you are actually fighting the World Government head- on openly," Jimbei said.

"Well, they are the ones who do wrong so why hide my own fight from others? And besides, they can't do anything for me except use despicable means to fight back."

"Well, Queen Otohime already heard it so she is asking if you need any help,"

"No need, we can easily fend for ourselves... by the way, are you guys going to start the meeting or what?"

"....."