The Space Empire Zangyack's invasion of Earth resulted in all 34 Sentai teams uniting and fighting the invaders in the Great Legend War. At the climax of the battle, all the Sentai teams were forced to sacrifice their powers to destroy the invasion armada and save the world. Their powers resurfaced as Ranger Keys which were spread across the universe. These Ranger Keys were collected by the Red Pirate Trio, AkaRed, Captain Marvelous and Basco ta Jolokia, as they knew that with them they would gain the Greatest Treasure in the Universe.
They had succeeded in collecting all the keys of the core teams, this was when AkaRed decided they were ready to find the treasure. But Basco, wanting the treasure to himself, betrayed his comrades and conspired with Zangyack to attack their ship. AkaRed managed to save Marvelous, giving him the chest containing the keys, before charging off into an army of Gormin. The attack was stopped and Marvelous became the captain of the Gokai Galleon, he later made friends with four people and formed the 35th Sentai team, the Kaizoku Sentai Gokaiger. Meanwhile, Basco became an ally of Zangyack, travelling in a modified Zangyack battleship, the Free Joker. He acquired a companion, Sally the space monkey, and found that there were more Ranger Keys. He found 25 new Ranger Keys, 15 keys for Sixth Rangers and 10 for Extra Heroes. Basco found that he was able to summon copies of past Rangers with them.
Basco decided to arrive on Earth to see Marvelous when the Gokaigers' total bounty exceeded that of the Red Pirates. After his inital encounter with the Gokaigers, Marvelous confronted Basco alone. Basco revealed to him that he has obtained Ranger Keys of Sentai heroes that AkaRed failed to mention to either of them. Using his trumpet, Basco summoned DragonRanger, KingRanger, TimeFire, Shurikenger, and DekaBreak to have them gang up on Captain Marvelous. However, though Captain Marvelous insisted that they not interfere, his crew arrived to even the odds. Basco's copies gave them a rough time at first, but the Gokaigers managed to gain the advantage. Though the Gokaigers managed to defeat the sixth hero Sentai warriors in one-on-one duels and return them to their original Ranger Key forms, the tables were turned in Basco's favor when he overpowered the pirates with KibaRanger, MegaSilver, GaoSilver, AbareKiller, MagiShine, Bouken Silver, Go-On Gold and Go-On Silver, Shinken Gold and Gosei Knight. With his crew brutally beaten without mercy, Captain Marvelous realized they were Basco's actual targets and he was powerless to save them. He was left with the Ranger Keys of the five warriors that were defeated as Basco took his shipmates captive.Ep. 15: A Privateer Appears
Basco later contacted Marvelous, offering to trade the Ranger Key chest, the Gokai Galleon and Navi for his crew, or he'll hand them over to the Zangyack for the bounty. After remembering the events that led to him joining the Red Pirates, Captain Marvelous regained his confidence and called Basco to arrange an exchange meeting with his crew present. Though he brought the Ranger Key chest, Captain Marvelous had no intention of doing the trade as he suddenly threw the treasure chest in the air while he fought Basco, spilling all of the keys and his own Mobilate in time for Doc (Gokai Green) to catch it with his mouth and using the Shinken Green Key to free himself and his shipmates before getting their Mobilates back from Sari. Basco then unleashed his 10 Super Sentai warriors and the Gokai Galleon crew assumed their Gokaiger forms to battle them while Navi gathered the Ranger Keys back into the chest and took them back to the ship. Defeating MegaSilver, GaoSilver, AbareKiller, Bouken Silver, and Shinken Gold, the Gokaigers used the Final Wave to take out KibaRanger, MagiShine, the Go-On Wings, and Gosei Knight. Deciding to take his leave, Basco sent a Giant Battle Pseudo-Lifeform which the Gokaigers swiftly destroyed. Back aboard the Gokai Galleon, the Gokaigers were pleased with their 15 newly-acquired Ranger Keys.Ep. 16: Clash! Sentai vs. Sentai
When the Black Cross King was resurrected, he used Basco's tactic and turned the Ranger Keys in the chest into copies to fight against the Gokaigers when they teamed up with the Goseigers. With the Goseigers and Gosei Knight uniting with the Gokaigers, the Ranger Key chest contained the keys of the first 33 Super Sentai teams along with the 14 Sixth Rangers before Gosei Knight, the Gokaigers having taken these keys from Basco shortly before.
The Gokaigers, now joined by Gai Ikari (Gokai Silver), arrived to claim their next greater power in the Ginga Forest. They discovered Basco, who intended to take the Gingaman's power for himself, attacking Hyuuga. To the Gokaigers' shock, Basco revealed he had more Ranger Keys than the ones they acquired before when he unleashed DekaMaster, Wolzard Fire and MagiMother to battle the Gokaigers, who told Gai to take Hyuuga to a safer place. Gokai Red attempts to advance toward Basco, but Sally blocks his attacks, while the clone extra warriors easily defeated the other four Gokaigers - sending them crashing into a river. When Gai was with Hyuuga, the former Black Knight requested that Gai give him the Gokai Cellular so he could become Gokai Silver.
Despite a long hesitation, Gai offered to lend Hyuuga his Gokai Cellular, but they were ambushed by Basco, who used his trumpet to drain the Gingamen's greater power from Hyuuga. Gokai Red intervened to stop Basco, who then unleashed a copy of Black Knight, Hyuuga's former Ranger Form, to battle him. During the fight, Gokai Red was attacked by the other three extra warriors. Hyuuga attempted to grab the Gokai Cellular lying on the ground, but Gai stopped him and recovers it before all of the Gokaigers regrouped. The main five Gokaigers changed into the Gingamen while Gokai Silver entered Gold Mode and defeated Black Knight with the Gokai Legendream. DekaMaster, Wolzard Fire and MagiMother were then eliminated by the Final Wave Gokai Blast. Luka (Gokai Yellow) eagerly went to claim the three keys, but they were snatched by Sally who gave them back to Basco. Later, Hyuuga handed Gai his Black Knight Ranger Key, having infused it with the Gingamen's power, telling him he had earned it. Ep. 20: The Lost Forest
Basco united his 9 remaining keys against the Gokaigers when they searched for the Ohrangers' ultimate power. Gokai Silver took on Wolzard Fire and Great Sword Man Zubaan, first turning into the Go-On Wings hybrid, and defeating the duo with Gold Mode. Wolzard Fire and Zubaan were enlarged and then finished off by Gai. The Gokaigers, turned into the Ohrangers, used the Olé Bazooka to take the 7 other copies down. Finally, the Gokaigers had taken all of Basco's keys, thanks to Gai shooting Sally before she had a chance to return to Basco's side with Keys in hand. Ep. 31: Crash!! Secret Operations
Basco's Gokaiger Keys
When Basco defeated the Gokaigers, taking their Ranger Keys and the Gokai Galleon, Navi escaped him. Basco had all windows and exits locked before summoning manifestations of the Gokaigers with his Rapparatta to retrieve the parrot. Shortly after, Joe, Luka, Doc, Ahim and Gai broke into the Gokai Galleon's engineering room and split up into two groups, only for them to encounter their respective manifestations. The Gokai Red manifestation captured Navi and returned him to Basco while the other Gokaiger manifestations returned to the living quarters. The manifestations revealed to Basco that they were the real Gokaigers, having defeated the manifestations and reverting them into Ranger Keys. Basco, however, used his powers to throw them out of the Gokai Galleon. He caught up with them and sent the Gokai Red manifestation to take them down, the Gokaigers countered by changing into Red Rangers. Don and Gai as Gosei Red and DekaRed fired at it with the Gosei Blaster and D-Magnum, then Luka and Ahim as GingaRed and MagiRed used the Blazing Mane and Ji Magika attacks on it, and Joe as DenziRed finished the manifestation off with Denzi Punch. Ep. 48: The Fated Showdown
Similar to how the Gokai Changes are the Gokaigers' equivalent of Kamen Rider Decade's Kamen Rides, Basco's summoning of Ranger Key Clones through his Rapparatta is considered to be the equivalent of Kamen Rider Diend's summoning of Kamen Riders through his Diendriver.
The Ranger copies from the Black Cross King in Gokaiger Goseiger Super Sentai 199 Hero Great Battle are seemingly weaker than Basco's summons. Normally, one or two of Basco's summons are equal to one Gokaiger, while the Gokaigers and Goseigers, 11 in total, were able to defeat the Black Cross King's army of 176 copies, with an individual Gokaiger or Goseiger being able to take on a whole team. This is obviously a convenience for the story, but the reason for this from an in-universe point of view is unknown. However, an explanation could be that Basco's trumpet energizes the Rangers he summons, making them stronger, or, the number of summons determines their strength, with the small amount Basco summoning being stronger than the at least 150 that Black Cross King summoned.
Strangely, the Gokaigers had already met two Extra Rangers before discovering the existence of the Extra Ranger and Extra Hero keys, having already met and received Greater Powers from Doggie Kruger (DekaMaster) and Kaoru Shiba (Princess Shinken Red).
The main five Goseigers and the Hybrids are the only Ranger Keys of the Super Sentai 199 that have never been summoned to become clones (not counting AkaRed, as he doesn't possess a Ranger Key of his own or AbarePink, as she is unofficial) and the Sentai who are not part of the Super Sentai 199.