Here is the Great Impel Down! An underwater prison where inmates will be held.
There are six Levels:
((Due to size, pictures of levels are links. They are safe to click))
Level 1: Crimson Hell
Crimson Hell (紅蓮地獄, Guren Jigoku?) is the first level of Impel Down in which prisoners are kept. While the level relatively is used for less wanted criminals, it contains a large forest of red trees. The leaves of the trees, known as Kenju (剣樹, bladed tree?), are as sharp as blades while the grass on the floor, the Haribarisō (針々草, needle grass?), is as spiky as needles. Here prisoners are forced to run through the forest while being chased by poisonous spiders and guards to experience all the pain from being cut from all directions. As consequence of prisoners being forced through this forest, it is soaked in blood. Deep within the forest is a hole that leads to Level 2. For those who do not wish to live through the pain of being cut any longer, they were given the option of jumping down the hole to Level 2, which contains an even more terrifying hell that nobody is willing to risk. The security here seems to be somewhat lax, as a prisoner has managed to sneak a Black Den Den Mushi into his cell, eavesdropping on what is happening around the fortress
Level 2: Wild Beast Hell
Wild Beast Hell (猛獣地獄, Mōjū Jigoku?) is the second level of Impel Down in which prisoners are kept. Buggy commented that every prisoner from level 2 that escaped with him holds a bounty higher than his own (15,000,000). It contains various wild beasts of sorts. The beasts kept here include Puzzle Scorpions and Manticores. Puzzle Scorpions are large poisonous insects that can join together to become giant centipedes. Manticores are man-eating human faced lions that will devour everything from their prey including the bones. Their human faces allow them to speak however they can only imitate what they hear like parrots as they don't understand what they're actually speaking. The words they speak are mostly things they heard from the prisoners so some of the things that they say are completely out of place. Among these regular-sized beasts kept here are also two gigantic beasts, the Basilisk and the Sphinx.
The Basilisk is a gigantic snake born from a chicken. It is a feathered mutant that possesses both snake and chicken traits. It is extremely strong that it gave Luffy and Buggy a good chase until it was downed with one blow of Gear Third from Luffy. Though formidable, the Basilisk is not the most powerful beast in the level. It is considered to be the "second-in-command".
The Sphinx is a gigantic human faced feathered lion. Significantly larger than the Basilisk and much more fearsome than the other beasts, it is considered the "boss" of the level and is charged with guarding the stairway that leads out of the level. It is so fearsome that the prisoners kept in the level, and even the other beasts hide from it. Like the Manticores, it is capable of imitated speech. It randomly says the names of types of noodles and apparently understands the concept of giving thanks before meals. It is such a strong beast that it is capable of breaking the floor beneath it if it hits it enough times.
With these various beasts, prisoners kept here are forced to be chased by them through the corridors of the level. Because of the fearsome danger, prisoners often either lose the will to go on, or refuse to escape even when their cells are unlocked.
Level 3: Starvation Hell
Starvation Hell (飢餓地獄, Kiga Jigoku?) is the third level of Impel Down in which prisoners are kept. Most of the prisoners kept here are pirates who have a bounty of 50,000,000 or higher. On this level, prisoners feel the heat rising up from Level 4 and are given precious little food and water to keep them in a near death state. They are reduced to the point where merely looking at them cannot tell that they were anywhere near once frightening criminals. And while the temperature here is nothing compared to the following level below, it is intense enough to cause overwhelming dryness, resulting in Level 3's somewhat desert-like terrain. Mr. 2 Bon Kurei was kept here, despite his bounty being only 32,000,000.
In the middle of the level is a large hole going directly to Level 4 down below. This combined with a gigantic fan directly above the hole, serves as the main ventilation system to redirect the smoke produced from below. Level 4 can be reached through this hole, however, to travel down it holds a risk of death or scalding by the fire and heat of the floor below.
Level 4: Blazing Hell
Blazing Hell (焦熱地獄, Shōnetsu Jigoku?, Inferno Hell in the Viz Manga) is the fourth level of Impel Down in which prisoners are kept. At this level, a pool lies filled with boiling blood heated by a raging fire making it extremely hot. The heat caused by this is so intense that it also heats up the level directly above it. If one tries to jump down to this level from Level 3 using the large hole used for ventilation above but don't land on a safe place, then they're dead.
Prisoners from other levels are regularly tortured here. The most prevalent form of torture here however is being thrown into the gigantic pot of boiling blood in the middle of the level.
Mr. 1 was kept here, though he was shown to be unfazed by the heat of this level while being placed in hard labor. He also saw Luffy and Magellan's battle while in his cell.
Magellan the warden of Impel Down stays here. His office contains a lift, which can take several people to all the Levels throughout the fortress, bypassing the stairs. This is also where the kitchen of the prison is located next to Magellan's office. Luffy's battle with Magellan was fought here prior to him being completely poisoned and captured.
Level 5: Freezing Hell
Freezing Hell (極寒地獄, Gokkan Jigoku?, Frozen Hell in the Viz Manga) is the fifth level of Impel Down in which prisoners are kept. This is the level where criminals with bounties of 100,000,000 and over are kept. In stark contrast to the level above it, the entire level here is a giant freezer. The level is so cold that not only do the prisoners kept here either freeze to death or lose pieces of their flesh from severe frostbite, but the food given to them is frozen to the level of being virtually inedible. Due to the extreme cold, Den Den Mushi don't function in this Level, thus cutting off both contact and surveillance, except on the locations localized around the entrances that connects Level 5 to the previous and next levels. Along with the severe cold, the level is inhabited by wolves. These wolves roam around the level like the beasts of Level 2, where they were originally stationed at. However, they proved to be too brutal to be in Level 2 as they also hunted the other beasts as well, including the Basilisk and the Sphinx.
Along with the bitter cold of the level, there seems to be a occurrence of prisoners mysteriously disappearing as well. Prisoners who are incapable of moving by themselves have been disappearing without a trace. Because of this, the Impel Down staff and the prisoners call this phenomenon, the "demoning away". The superstition is that the missing prisoners have been actually pulled away by demons to the Gates of Hell itself. The belief of this superstition has been carefully kept within level 5 so that no inmates from the upper levels were aware about it prior Bon Kurei (disguised as Hannyabal), Buggy, and Mr. 3 descending down to it where they were informed by the guards. Among these missing prisoners is Emporio Ivankov, the queen of the okama. He was imprisoned here until he mysteriously disappeared from his cell. Since then he was rumored to be living in an abandoned guard's office deep within a forest situated in the level.
Level 5.5: New Kama Land
Known as the The "Prisoners' Secret Flower Garden", New Kama Land (ニューカマーランド, Nyūkamā Rando?) is a hidden sub level of Freezing Hell, and is where all the prisoners who have been supposedly "demoned away" have gone to. The secret area is located inside a rock between Levels 5 and 6. It was carved out long ago by a prisoner with a tunneling Devil Fruit power, and is a secret location unknown by the jailers. It is ruled by the "Queen" Emporio Ivankov, and it's called the Okama Paradise where all the Okama and prisoners party and have fun at all times. Indeed, it has been described by Iva as a "paradise within hell", and true enough, not one inmate from this hidden level is inclined at all to escaping the Great Jail as a result. However, since the level itself is hidden, the inhabitants seem to abide by very strict rules that prohibits them from actively interacting with the other levels, at least not without covert movement. Still, they don't seem to discriminate should new arrivals found their way here, as seen by the warm welcome they gave to Bon Kurei
One of its main rooms is a combination of a sit-down cafe and a discotheque, with the main attraction being a cabaret stage where Emporio Ivankov and his followers perform. Apparently, there are also secret entrances existing from the other levels (save for Level 6) that leads directly into this hidden level which the inhabitants can take advantage of in procuring the necessary supplies. The level also has a Surveillance Den Den Mushi that captures feeds from Impel Down's main surveillance system so the prisoners can see what's going on from all levels in the prison. They also steal newspapers from the prison's garbage cans to stay informed of current events.
Its name is a pun on New Comer and Okama, and refers to the Okama who are completely able to change genders thanks to Ivan's powers. In Japan a "New Half" is a man who undergoes a "sex-change" operation.
Level 6: Eternal Hell
Eternal Hell (無限地獄, Mugen Jigoku?) is the lowest level of Impel Down. It is where prisoners who are insanely powerful, have caused crimes extremely atrocious, and/or whose mere existences have become a major threat to the World Government itself are kept. Sengoku said even a single Level Six prisoner lurking in remote country could be an incredible danger to the public. The prisoners on this level have been given either the death penalty or a life sentence. They are basically "erased" from history.
Ace was kept here on death row, awaiting his execution. Because most people dismiss Level 6 as just a rumor (until its actual discovery) Ace was believed to be on Level 5 by other prisoners. Jinbei was also placed on this floor, and was being kept in the same cell as Ace. Though the prisoners on this floor are either jailed for the rest of their lives or until their execution day arrives, Jinbei was only given a temporary sentence for refusing to fight against Whitebeard. Crocodile is also being kept here in a cell next to theirs. Near them are various other legendary pirates who hold deep grudges against Whitebeard, some of which are several imprisoned Giants.
Kept alongside the prisoners is the former Chief Guard Shiliew. Because he constantly massacred prisoners, he was deemed to be a menace even within Impel Down, and became too dangerous to be kept anywhere else in the prison. For abusing his powers, he was sentenced to Level 6, until his death sentence. Interestingly enough, even though Level 6 is considered the worst hell, prisoners kept here are never actually tortured. It simply seems to be a holding cell for life or until an execution and prisoners do not have to endure terrible conditions (burning heat, freezing cold, etc.) unlike the higher floors. However, as seen with Jinbei and Crocodile as they moved through the other levels and are unaffected by those conditions, the inhabitants of this level may simply be too powerful to be affected by torture. However, solitary imprisonment has been proven to be an effective torture in the real world, where even Shiliew stated that the boredom made him wish for death.
