It seemed that my father, like all my ancestors, had been hiding their wealth in a secret place for generations, each one adding to the treasure hidden behind a door that, if McSweeney's story is true, only a Cooper can open.
― Sly Cooper[src]
The Cooper Vault was a large cave system located on Kaine Island in the South Pacific. Believed to be originally modified by Slytunkhamen Cooper II around 1300 BC into a vault, it contained the fortune and canes of many members of the Cooper Clan. The vault door was virtually indestructible, and only a true cane belonging to the Cooper clan is capable of opening it.
It is not completely known who originally started using the cave system as a vault, though the first member who had treasure and a pedestal was Slytunkhamen Cooper II, who lived around 1300 BC.
As time went on, many of the more prominent members of the Cooper Clan made a trip to Kaine Island, where they stored their gold and treasure, as well as traveling further into the cave system where they set up a pedestal that held their cane and a self-portrait of some form. They then surrounded this shrine with their most prized possessions, ranging from vases and bags of money, to swords and wanted posters.
Eventually, a large door to seal the vault was installed. It could only be opened by placing a true Cooper cane into the shaped "keyhole."
The components of making a first Cooper Vault is unknown due to its strong durability and resistances even Dr. M's year of work could not even punch through the Cooper Vault.
Dr. M's fortress
For years, he tried to break through the door to take the fortune inside the vault. He attempted to use drills and lasers to break through, as well as fake Cooper canes. However, all of these attempts failed as the vault was indestructible and could only be opened by a real Cooper's cane. Over time, Dr. M grew paranoid and built a powerful fortress surrounding the entire island, guarded by his genetically created henchmen. According to Sly, Dr. M's security was "as tight as Fort Knox", forcing to expand the Cooper Gang with additional members to have a chance of breaking in. During Honor Among Thieves, Sly Cooper, Bentley and Murray finally gained access to the inside of the vault using Sly's cane.
Despite the entire gang having gained access to the vault, only Sly had the skills to traverse the ancestors' gauntlet. While he explored the legacy of the Coopers, Dr. M finally broke into the vault. Bentley and Murray held him off for as long they could, but he eventually got free of them and followed Sly through the gauntlet using a tracking device he had planted on Sly's cane before they entered the vault.
As Sly found the inner sanctum, Dr. M met up with him, and they fought. After the fight they began arguing about the integrity of Sly's friendship with his team. At that moment, Carmelita arrived partway through the battle and attacked Dr. M after Sly took a shot for her. Defeating Dr. M, Carmelita and Sly left as the entire vault began to cave-in due to the intensive battling. Dr. M refused to escape, as he sought the treasures for decades and presumably died in the cave-in Bentley headed in to the sanctum to find Sly, but only found his cane, as well as an intact section of the vault filled with a fortune's worth of gold.
Between Sly 3: Honor Among Thieves and Sly Cooper: Thieves in Time, Bentley and Penelope became the keepers and maintainers of the remaining Cooper Vault, making repairs to it and creating new security for it, including a new vault door.
Inside the vault was all of the fortune and wealth of the Cooper line, and a pedestal that displays the cane that each of the prominent Cooper members owned. The vault also had many booby-traps only a Cooper could get through, ranging from Ninja Spire Jumps to Rail Walks. The entire treasure trove in which the Cooper had placed their treasure had been placed at the very end of the vault inside the inner sanctum, which held not only treasure, but some of the Coopers' greatest inventions, such as Thaddeus' helicopter.
Treasures and canes
- Slytunkhamen Cooper II: Presumed founder of the vault, ancient Egyptian thief - Twin khopesh-like canes, a sarcophagus
- Salim al-Kupar: Arabian thief with the stealth of 40 thieves - Scimitar-like cane, a rug and Arabian lamp
- Sir Galleth Cooper: Honorable knight and cunning thief - Lance-like cane, his shield
- Slaigh MacCooper: Scottish thief and also known as the strongest of the clan - Stone-topped caber cane, his wooden shield
- Rioichi Cooper: Japanese ninja thief - Twin sai-like canes, a suit of samurai armor and a jade dragon
- Henriette Cooper: Pirate thief - Hook-like cane, a cannon
- "Tennessee Kid" Cooper: Western American outlaw and railroad thief - Pistol-like cane, a wagon wheel and a horn from a steer
- Thaddeus Winslow Cooper III: British aristocrat and gentlemanly thief - Ruby embellished cane, cup/goblet
- Otto van Cooper: Outstanding mechanical thief - Propeller-like cane, tool boxes and his plane
- Conner Cooper: Scientific thief and proud father of Sly Cooper - Cane (now belonging to Sly), a laptop and a microscope
- Despite Salim having lived before Sir Galleth, Galleth's section is closer to the entrance than Salim's.
- According to Sly, every Cooper stored their wealth in the vault. However, it is unknown if all Coopers built a shrine, as only a small amount are seen.
- Bob Cooper, the minor Coopers, Slytunkhamen I, Sly's mother, and Sly himself are the only members that do not have known sections in the Cooper Vault.
- Slytunkhamen I likely passed away before Slytunkhamen II created the Cooper Vault, which could be an explanation as to why he does not have a section in the vault.
- Despite the vaults seemingly impenetrable fortification that only a Cooper can bypass, Bentley was able to enter the inner sanctum and Carmelita was able to break through a back entrance. There was also a cave opening that led to the Cooper fortune hidden only by some bushes that Sly left open for the rest of his gang.
- The operation itself was in fact not a heist on the Cooper Vault; instead the operation was done to "rescue" the vault and its contents from the hands of Dr. M.