Impel Down

Impel Down is the World Government's maximum-security prison for the most dangerous criminals and pirates. It is located underwater, somewhere beyond the Gate of Justice.

The name derives from The English verb 'impel', meaning to force.

The known way, so far, to get to Impel Down is through the Gates of Justice at Enies Lobby.

Current known prisoners:
 * Mr. 0 Crocodile
 * Mr. 1 Das Bones
 * Mr. 2 Bon Clay
 * Mr. 3
 * Portgas D. Ace

Crocodile and Mr. 1 were imprisoned in a Marine base, but were transferred to Impel Down after most of the captured Baroque Works members escaped (Crocodile and Mr. 1 chose to stay behind). Bon Clay and Mr. 3 were captured by Hina, and presumably transferred to Impel Down for reasons similar to Crocodile and Mr. 1's transfers.

Defeating Portgas D.Ace led to Blackbeard becoming a Shichibukai, and them Ace was sent to Impel Down. Ace is currently sentenced to public execution.