Impel Down Arc

The Impel Down Arc is the twenty-first story arc in the series, and the third in the Summit War Saga of the One Piece series, continuing from the Amazon Lily Arc. Luffy puts finding his crew on hold in favor of rescuing his brother Ace from the underwater prison Impel Down. With some assistance from Boa Hancock, he manages to infiltrate the facility. However, fulfilling his objective and escaping the hellish prison might be easier said than done.

Story Impact

- Luffy begins his attempts to save Ace by going to Impel Down. On his way down, he meets old foes he has faced back in previous arcs including Buggy, Mr. 3, Mr. 1, and Crocodile. He met an old ally, Mr. 2 Bon Kurei as well as new allies who know Dragon: Ivankov and Inazuma, and a close friend to Ace, the Fishman Shichibukai Jinbe who all help Luffy save Ace in the Whitebeard War. Though he was the second Shichibukai to be named back in the Arlong Park Arc, Jinbe is the final Shichibukai to be fully shown.
- Jinbe being a close friend to Ace is revealed and their past encounter is foreshadowed, which was later shown in the Marineford Arc. Whitebeard's protection of Fishman Island is introduced. Jinbe's connection to Whitebeard caused him to resign his position of Shichibukai in the next arc.
- Crocodile's grudge against Whitebeard is revealed as he was simply trying to help Luffy escape Impel Down so he can try to kill Whitebeard at Marineford.
- Ace's loyalty to Whitebeard and his disdain for his birth father are presented for the first time.
- Blackbeard's true reasons for becoming a Shichibukai are foreshadowed and later revealed in the Marineford arc.
- As stated by Vice Admiral Momonga to Hancock, Shanks has engaged his fellow Yonko, Kaido, in hopes of protecting Whitebeard after Kaido's attempt to take Whitebeard's life while he was heading to Marineford to save Ace. What happened between Shanks and Kaido is unknown.
- After getting poisoned by Magellan and surviving thanks to Ivankov, Luffy gains a natural resistance to poison which helps him survive against Hyouzou's poisonous ink in the Fishman Island Arc, and Caesar Clown's gases in the Punk Hazard Arc.
- With Blackbeard having gained new crewmates from Level 6 due to his death match, several Level 6 inmates would escape. Sengoku would hear of this and after hearing the World Government wanting to suppress this incident, he and Garp would resign from the Marines after the war. Magellan would also be beaten to an inch of life left in him as revealed in the Post-War Arc, causing him to want to take full responsibility for this incident. After the timeskip, Magellan would be replaced as Warden by Hannyabal and demoted to Vice Warden. During the timeskip, a bounty hunter named Jean Ango would reveal he learned the location of the Level 6 inmates.
- The prisoners mentioned by Ivankov in his talk with Bentham would later become the new recruits to the Blackbeard Pirates in the following arc.
- Crocodile's connection to Emporio Ivankov is revealed as well as his past being foreshadowed when Ivankov blackmailed him to help or he will reveal his "secret".
- Bentham's fate after his battle with Magellan is unknown but it will later reveal him to be alive and well as the new "Queen" of Newkama Land after the timeskip.
- Buggy's past as a member of the Roger Pirates is revealed to the fellow escaped prisoners of Impel Down who will later worship him and follow his every move in next arc. Also his past will help earn him a place as Shichibukai during the timeskip.
- In this arc, Crocodile would reveal that Zoan users have a class known as Awakened. This would be further explained in the Dressrosa Arc about Devil Fruit users having an Awakened class for all types.