Layout and Locations
The Drum Castle is an icy-looking castle surrounded by a small forest of pine trees.
After Wapol departed from Drum Island, Dr. Kureha used this opportunity to occupy the now vacant castle, turning it into her new workplace. As a result of this, the castle was redecorated with creepy shamanic furniture (fitting Kureha's witch theme), research tools and medical equipment for the treatment of patients.
The interior of the castle itself is very cold and filled with snow due to the front door being always open. This was done to accomodate the snow birds that had settled in, with Tony Tony Chopper being responsible for their care.
The Royal Drum Crown 7-Shot Bliking Cannon can be found in one of the castle's upper rooms.
The infirmary is where Kureha keeps her patients that are under treatment.
This is where Nami stayed as she recovered from her illness. She was later joined by Dalton, who had been gravely injured during his prior confrontation with Wapol at Bighorn.
The castle features an arsenal filled with weapons of various kinds. Wapol could use his ability to devour and then merge himself with all the weapons inside, having employed this tactic once against Dalton in the past.
According to Dalton, Wapol was always in possession of the key to the arsenal room, carrying it on his left hip at all times. Nami was able to steal this key from Wapol before he could make use of the arsenal's weapons a second time. Later, after Wapol's defeat, Nami gave the keys to Kureha, who instructed some of Dalton's men to fire Hiriluk's cherry blossom powder into the atmosphere through the arsenal's cannons, leading to the island's now signature pink snow.
Before, the top of the castle featured the flag of the Drum Kingdom, but according to Kureha, she burned it down to make way for Hiriluk's. Wapol attempted to shoot it down, but thanks to Luffy, the flag remained intact.
Wapol ruled the Drum Kingdom with an iron grip from the safety of the Drum Castle, which once was the household of the Drum Kingdom royal family. To tighten his control over the population, Wapol started the Doctor Hunt, which forced all of the kingdom's doctors to relocate to Drum Castle under the threat of death should they not. This gave Wapol absolute power over his subjects, who now had to beg for medical treatment. By the end of the operation, Kureha and Hiriluk were the only remaining independent doctors in the country
Annoyed by Hiriluk's antics and never managing to capture him, Wapol schemed a trap for the quack doctor, coming up with a fake story about the Isshi-20 requiring urgent treatment. Hiriluk was successfully lured towards Drum Castle, but avoided being executed since he was already planning to blow himself up in the end. Outraged by Wapol's behavior through the whole operation, Dalton rebelled against his king, who made use of the castle's arsenal combined with his Devil Fruit in order to defeat his now former servant. Dalton was then imprisoned for his insolence.
Eight years later, Marshall D. Teach and his crew attacked the kingdom, causing Wapol to flee the country in panic and abandon Drum Castle. Kureha took over the castle for herself, moving out from her previous home near Gyasta. She and Chopper would occasionally descend from the castle through their own custom ropeway in order to look for patients to treat.
Drum Island Arc
When the Straw Hat Pirates arrived on Drum, they learned about the castle and its new owner Kureha from Dalton and the locals. As Nami was almost lethally sick at the time, Luffy and Sanji hurried to the castle while carrying her through Drum's deadly geography, climate and fauna.
Managing to reach the castle and having the ill Nami and a wounded Sanji treated thanks to Dr. Kureha, Luffy met his future crewmate Tony Tony Chopper. Wapol had returned to his homeland and attempted to retake his former property. Luffy and Wapol fought outside and within the castle's walls, resulting in the former dealing a tremendous blow to the latter, which was enough to blast the tyrant off Drum Island.
The Straw Hats then left the castle with Chopper's help by descending through the ropeway he and Kureha had installed.
Fish-Man Island Saga
From the Decks of the World
Currently, the castle now serves as a medical academy where Kureha teaches medicine, having expanded the previously twenty doctors of the kingdom into one hundred.