Shichibukai were the seven great pirates recognized by the World Government as privateers.
As long as one could secure this position, one could enjoy the privileges and conveniences granted by the World Government.
For example, legalized plundering and no longer being hunted by the Marines were among those privileges...
In other words, once one became a Shichibukai, there was no longer any need to worry about harassment or threats from the Marines. One could naturally act more freely and have far fewer concerns.
In return, however, the Shichibukai had to answer the World Government's compulsory summons and hand over part of their profits, including those from privateering.
These were the obligations that came with obtaining such privileges.
As a result, pirates generally regarded the Shichibukai as the World Government's lackeys.
In reality, though, becoming a Shichibukai was no easy task. Only those with great fame or enough strength to intimidate ordinary pirates were qualified to be selected as Shichibukai.
Take Fire Fist Ace, whose reputation had risen sharply in recent years. Before joining the Whitebeard Pirates, he had once been invited by the World Government to become a Shichibukai.
Many of the Shichibukai's privileges could indeed allow Hunter's Notebook to be put to highly efficient use.
For example, he could offer the Marines a condition they could not refuse, then use his status as a Shichibukai to request permission to execute some criminals without Devil Fruit abilities at Impel Down.
The Marines might agree, and perhaps even provide information about the prisoners.
Most of the prisoners in Impel Down endured torture every day. Those who could withstand it certainly would not have weak constitutions, making them highly suitable prey.
Alternatively, he could make hunting pirates the premise for requesting intelligence support from the Marines. They would surely agree readily.
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