It is undeniable that Aokiji's continued stay in the Marines is indeed very helpful to Sakazuki, but the current situation does not allow it.
If the Five Elders discovered that their relationship with Aokiji had not broken down after the battle, and instead they had grown closer, they would definitely target the Marines and restrict their development.
This would be extremely detrimental to the Marines, who had just experienced the War of the Best and suffered heavy losses.
What the Five Elders need is a Marine force full of internal conflict and disorganization, not one working together in harmony. A united Marine could become a threat to the World Government.
What Sakazuki has to do now is secretly develop, build strength, and clean up dissidents within the Marines.
"Accumulate resources broadly and build power slowly!" he thought. Gradually, Sakazuki planned to break away from the World Government's control and create an independent Marine.
He envisioned a future where the Marines would no longer serve as a military organization begging for scraps from the World Government but stand as a powerful, independent entity.
"After you leave, the Marines will only have one Admiral left—Kizaru. During the world conscription, we won't just replenish the Marine ranks to face the evil era Whitebeard has unleashed. We will also fill the two vacant Admiral positions!"
"The Five Elders must think the new Admirals won't be under my control, and since Kizaru has a personality that resists orders, they will believe I pose no threat to them while isolated!"
Sakazuki's tone was calm, yet his words carried profound insight.
After hearing Sakazuki's explanation, Aokiji suddenly understood. "Then, what do I need to do after quitting the Marines?" he asked.
"The first step is to head to Fish-Man Island!" Sakazuki said. Fish-Man Island was a strategic location, situated 10,000 meters beneath the holy land of Marie Geoise. It served as the only route to the New World.
Pirates aiming for the New World needed to coat their ships at Sabaody Archipelago, dive to the seabed, and pass through Fish-Man Island to reach their destination.
Sabaody Archipelago was a chaotic area and the unofficial backyard of the Celestial Dragons. At present, the Marines had little control over it, making Fish-Man Island the best starting point for their plan.
"With your strength, you can easily eliminate all pirate groups heading for Fish-Man Island!" Sakazuki added.
Suddenly, Sakazuki unleashed his Haki. Though confused, Aokiji instinctively became alert.
"In addition, there's an Ancient Weapon hidden on Fish-Man Island—Poseidon, the Mermaid Princess, and daughter of the current King of Fish-Man Island!" Sakazuki revealed.
Aokiji's face was filled with shock as he used his Observation Haki to scan his surroundings cautiously.
"Sakazuki, you're incredible! You even know about Poseidon!" Aokiji exclaimed, marveling at Sakazuki's effort to gather such classified information.
If Sakazuki could hear Aokiji's thoughts, he would have laughed. "The scope is too narrow," Sakazuki might say. "I know about all three Ancient Weapons."
"Whether to guard against the World Government or to prevent others from targeting her, we must ensure she's under our control!" Sakazuki said firmly. He then took out a black Den Den Mushi from his desk.
Aokiji recognized the advanced communication device. It required identity verification and was designed to protect undercover operatives. Only a few major powers possessed such technology.
When Sakazuki handed the device to him, Aokiji knew it was time to act.
"Time waits for no one. Delays can bring complications. The sooner you leave, the better!" Sakazuki said.
Aokiji took the device without hesitation and turned to leave, but Sakazuki stopped him.
"Wait a moment. Take this book! Before we fully succeed, this will be our motivation to keep moving forward!" Sakazuki handed him a book titled Absolute Justice from his desk.
Though there were rubbings of the book available, Sakazuki decided to give Aokiji the original copy as a farewell gift.
Aokiji accepted it gratefully and hid it deep in his coat pocket like a treasure. Then, under the cover of darkness, he left the Marine Headquarters.