Queen indeed mentioned a rule, but it's not a rule for all pirates.
Ordinary pirates forming alliances or some acquaintances among pirates choosing to join the other side naturally don't need a formal pledge. However, for someone like Who's-Who proactively joining a large pirate group, not having a proper pledge wouldn't make sense.
If he were just a newcomer with decent strength, it wouldn't be so troublesome, but his previous identity as a formal member of CP9 means he has to prove himself truly severed from the World Government.
Although he's been wanted, whether someone is wanted or not is just a word from the World Government, which can be fabricated and has no credibility at all.
"Is my strength not enough?"
"Strength? Mwahahaha, you rate yourself too highly. Your strength hasn't reached a level where we would break the rules for you.
But I won't make it hard for you. Since you're a former CP9, you should have some understanding of CP0 too."
Who's-Who isn't weak, but in the current Hundred Beasts, that's not enough. The intelligence he can offer far outweighs his martial value.
CP9 and CP0 hold a special place within the World Government's agencies. Formal CP9 members can be seen as reserve personnel for CP0. The World Government recruits suitable children from all places, then sends them to a special island for brainwashing and special training.
Under normal conditions, they would never betray, as seen when Lucci was almost killed by a Buster Call during the Judicial Island incident and was hunted afterward, but ultimately returned to the World Government, becoming part of CP0 once more as a lackey to the Heavenly Celestial Dragons.
In the case of Who's-Who, he can be considered an exception.
Due to CP9's training methods, they essentially align with CP0's primary requirement: loyalty.
Who's-Who and Rob Lucci were the two most talented recent CP9 members, and Queen believes they might have had access to some special intelligence.
"Some, but not much."
Who's-Who isn't foolish. Since Queen spoke this way, he naturally understood what Hundred Beasts was interested in, and he was no longer planning to keep these things secret. With the World Government wanting to eliminate him, he needed to make himself as invaluable to the other side as possible.
However, some of the information was already outdated, and some was nearing obsolescence, so he didn't know how much value these things could actually hold.
"Very well, then let me ask you, back in 1509, there was a CP0 named Knight who carried out an operation in the Kogia Kingdom of the East Sea. Why did CP0 know my whereabouts at that time?"
"The then King sold you out."
"Oh? So sure? How do you know that?"
"I read the intelligence on that mission. Initially, it was intended for CP9 to handle, but was later changed to CP0. By the way, Knight is still alive; you didn't kill him then."
Having been involved, Who's-Who gave a direct account of that matter, which was merely a trivial tidbit compared to what he knew.
"Great, very good, then the heads of that King and the strategist back then will be your pledge to join us. I'll give you four months to accomplish this, and then you can join us."
If not for the situation not permitting, he would have thought about a full-scale bombardment of that country to show they weren't to be trifled with.
Though not going to such extremes, retaliation was certainly on the table.
A pledge doesn't necessarily have to be a gift; such actions can function as a pledge.
"Four months..."
"Any issues? Don't worry, I'll arrange a ship for you, so you won't be delayed on the road."
"No, I'll take his head."
He broke out because he didn't want to die; trading someone else's head for his safe environment didn't trouble his conscience at all.
Quickly, Queen arranged a ship for him, and instead of returning to Ghost Island, he stayed here waiting. If Who's-Who had other intentions, then leaving Ghost Island would be enough bait for them, and all he had to do was wait.
However, he didn't get any results. After a while, Queen safely returned to Ghost Island, while simultaneously, Tiger embarked on his pilgrimage.
...
"Ah Long, stay out of trouble during this time."
Apart from Ah Long, there wasn't anyone Tiger was worried about. He'd been quite calm recently, his greatest interest being riding the Ferris wheel dozens of times a day, but all that was under the premise that Tiger hadn't left.
Now that he was leaving and couldn't conveniently take Ah Long along, Tiger was inevitably a bit worried.
"Got it, big brother. I'll stay on Fishman Street and won't go anywhere else."
With Tiger leaving, Ah Long also planned to go back to Fishman Street for a look. With Otohime's help, a stable tourist route had almost been established between Fishman Island and this island, with an increasing presence of Fishman Race and Mermaid Race children here.
This even included adult members of the Fishman and Mermaid races, whose longing for Shampodi Paradise was being fulfilled here.
Seeing the environment here, Ah Long even reminisced about the old days on Fishman Street, especially during his childhood. This place looked exactly like the paradise he had dreamed of as a child.
"But big brother, you'd better come back soon."
"I will. There's still a lot to do when I get back."
Patting Ah Long's shoulder, Tiger left with Mandfeish's ship heading towards Ghost Island.
"Let's go."
Shortly after their departure, Sharley's voice sounded behind Ah Long; this time, not only Tiger left with Mandfeish, but Rushaka also went with him, wanting to see Mandfeish's headquarters.
Before leaving, Rushaka told Sharley she could stay, but with the host gone, staying as a guest didn't feel right, so she temporarily returned to Fishman Island with Ah Long.
Although Ah Long had become a lot more normal recently, not as extreme as before and not reacting excessively when seeing humans on the island, Sharley still didn't like him.
This was partly because he had been inexplicably concerned with everything lately, including concerning himself with her lifelong affairs.
To Ah Long, it seemed there was something between Sharley and Mandfeish. Being straightforward, and with Sharley unwilling to talk to him, misunderstandings inadvertently deepened.
...
Throughout the journey, Tiger didn't speak much, spending most of his time going through the Arceus Sect scriptures that Mandfeish had found for him.
This doctrine was still the handwritten version from Misu, and during interactions, the two devotees found their thoughts aligning, gradually regarding each other as kindred spirits.
When the ship arrived at Ghost Island and Mandfeish went to call Tiger, for some reason, he seemed to see a light emanating from him...