Chapter 538

The 538th Chapter of One Piece is called "Level 5.5-New Kama Land".

Level 5.5, New Kama Land
Iva starts this chapter by saying that he will take 10 years off Luffy's lifespan in order to save him. However, Iva states that this will not definitely save him, but raise his chance of survival from 0% to 2-3%. He also states that Luffy needs to have great willpower to save him and then injects Luffy with "Emporio: Healing Hormones". Thus, Luffy began screaming and would do so for 10 hours.

Mr. 2 is astounded at what Iva did. Iva explains that all he did was draw out energy from Luffy and bolstered his immune system, to a point where it was capable of fighting Magellan's poison. He also says that hormones and willpower are what a human needs to get saved. However, Mr. 2 looks in and to his horror, Luffy was still screaming. He begs Iva for Luffy to be released, only to be hit by Iva.

Iva shouts at Mr. 2, saying that he has never helped a poor man relying on others but saved countless countries from poverty. Iva states he is no "miracle worker" but that only REAL miracles descend on those with willpower. Iva then explains his Devil Fruit ability, the Horu Horu no Mi. He says he is an 'engineer' of the human body, where his ability allows the change of body temperature, pigmentation, gender, growth,emotional state and etc; simply the power to remodel the human body from within.

Iva then starts talking to Mr. 2 and tells him that he already seems like a "New Kama". Iva says that those around him had truly transcended gender, that men here were woman and vice versa. He then says that every person here and accidentally wondered in, by using secret entrances from any Level from 1-5. He states that they had their own monitor room and that they stole newspapers to keep up with the outside world. Iva also added that they enjoyed watching Luffy's break in to Impel Down, saying it was "top class entertainment".

Mr. 2 then asks about how this place was created as they have so much space. Iva simply replies with that there was nothing. But then a man with a Devil Fruit that gave him a "tunnelling" ability. He then reveals that he dug Level 5.5 out and that it was in the middle of Level 5 and Level 6! To Mr. 2's surprise, Level 6 exists, where Iva states only the world's most atrocious criminals and that they had been deemed fit to be erased from history.

Iva then goes on about Luffy's attempt, that if he tried his attempt earlier, it would've failed as there was a man named Shiryuu "of the Rain", who was the head gaoler at Impel Down. Shiryuu was known to be stronger or at least equal to Magellan. With Magellan and Shiryuu, the "Stars" of Impel Down, it was truly impenetrable.

Magellan and Shiryuu
Shiryuu was seen standing holding a blood-covered sword with a number of prisoners surrounding him. Magellan stood up for the prisoners, with Shiryuu replying with that the prisoners were trash. Nothing more is revealed but it is assumed that Magellan took on Shiryuu and defeated him and eventually imprisoned him in Level 6

Level 5.5, New Kama Land
It was revealed that Shiryuu went on a rampage slaughtering prisoners, randomly and was deemed fit for Level 6. Iva goes on and names three other Level 6 prisoners:Catarina Devon, the most dangerous female prisoner, "Colossal Battleship" San Juan Wolf and "Mighty Drinker" Basco Shot. Iva says that Mr. 2's former Boss, the former Shichibukai is also imprisoned there. Also Ace was being held there and the "Knight of the Sea", Jinbei was being held also in Level 6. Iva also reveals Ace's execution time, 1500 hours and that he will be moved in the morning, transferred to the Marines and moved to Marineford.

Iva also suggests that Luffy has to stay in that condition for another two more days but Ace is to be moved in eight hours(0000 hours at the time). A glum Mr. 2 is told to rest and eat himself, but he shouts that he would go and sleep in Luffy's room. Later, Iva and the other New Kamas watch Mr. 2 shouting at Luffy's room, telling him to hang on, to make it out alive.

Level 3
Sadi-chan is seen whipping the Four Demon Guards, saying that couldn't even find an okama.

Level 5.5 New Kama Land
Mr. 2 is seen again, shouting words or encouragement but this time joined by others, shouting Luffy on.

Chief Magellan's Office, 3 Hours Later
A Gaoler reports that someone had finished completely vanished from Level 5, most presumably Mr. 2.

Level 4
Gaolers discover Hannyabal, strung up in the weapons room.

Level 5.5, New Kama Land, 7 Hours later
Everyone is seen cheering Luffy on, from Mr. 2 to Iva.

Level 6
Jinbei suggests to Ace that Hancock had simply lied to him, but Ace refuses to believe that. Ace says that Luffy was always doing reckless stuff and that he always made him worry.

Chief Magellan's Office, 8 Hours Later
Domino quickly states to Magellan, who was sitting on the toilet at the time, that the time for Ace's transfer had arrived.

Level 5.5, New Kama Land
At one point, Luffy stops screaming. Iva states that the pain should not cease at any point during the healing process and indicates that Luffy had died, as blood had come under the door. But then, someone from INSIDE the chamber(Luffy) attempts to bust down the door and instead, shouts FOOD!. To everyone's surprise, Luffy is alive, especially to Iva's as it had only been one day.

Characters

 * Level 6 prisoners who have been mentioned.
 * "Colossal Battleship" San Juan Wolf
 * "Mighty Drinker" Basco Shot
 * Catarina Devon