Operation Delta Rising

 was the codename for the return of the Federation and its allies to the Delta Quadrant using the Iconian Gateways in the Jouret System, Solanae Dyson Sphere and Jenolan Dyson Sphere that led to the region travelled by USS Voyager during the latter part of its journey.

Prelude
In 2371, the Federation starship USS Voyager was pulled into the Delta Quadrant by an entity known as the Caretaker and began a 70,000 light-year journey back to Federation space. Five years into the ship's journey (2376), Voyager accidentally came across the Underspace tunnels through subspace and were pursued by a Turei patrol. Seeking to evade the Turei, Voyager landed on an uninhabited planet - now known to be Vaadwaur Prime - and discovered a number of Vaadwaur in stasis. After awakening the Vaadwaur, the crew of Voyager learned of their nature as an aggressive and expansionist species in time to prevent the awakened Vaadwaur from stealing the ship. Using a number of small craft from the planet, the Vaadwaur escaped before they could be returned to stasis.

Over the next thirty years, led by Gaul, the escaped Vaadwaur would locate and awaken other Vaadwaur forces in stasis while seeking a means to reclaim their power and territory. During this time, in a hidden part of Underspace, Gaul would make contact with the Iconian Servitor races. Through this contact, the Vaadwaur would gain advanced technology to bring them even with the other Delta Quadrant races and many Vaadwaur would be implanted with Bluegill parasites for increased strength and resilience.

Opening Shots
Some time in 2409 or early 2410, the Vaadwaur moved to reclaim their worlds, including Vaadwaur Prime and Kartella Prime. They would launch a devastating blitzkrieg on the Krenim Imperium leaving no appearent survivors. Skirmishes with the Borg would also end with the outcome in the Vaadwaur's favor. The only place where the Vaadwaur were forced into prolonged conflict was Kobali Prime.

Delta Alliance
In 2410, the discovery of a chain of Iconian gateways leading from the Jouret System in the Beta Quadrant to the Solanae Dyson Sphere on the edge of the Delta Quadrant and from there to the Jenolan Dyson Sphere which had jumped from its former location in Federation space to a location in the Delta Quadrant near the Nekrit Expanse would cause the Federation, the Klingon Empire and the Romulan Republic to form the Delta Alliance to lead joint operations in the Delta Quadrant. Delta Quadrant Command was established in the Jenolan Dyson Sphere and the Alliance began reaching out to races encountered by Voyager during its journey including the Talaxians, Ocampa, Benthans and The Borg Cooperative. During these operations, the Alliance would begin seeing their first signs of Vaadwaur activity, at the time unidentified as such, in the form of devastated battlefields.

Revelations
During a skirmish between Alliance and Voth forces, both sides answered a general distress signal from the Turei homeworld which was under attack from an unidentified adversary. While the Voth acted to protect the Turei from orbit, Alliance ground forces beamed down to a Turei defense headquarters to provide assistance where the Turei revealed the identity of the attackers as Vaadwaur. After the battle's conclusion, Admiral Tuvok arrived to speak with the Alliance commander and admitted that Alliance intelligence services did not consider the Vaadwaur as a threat based on the information from 2376.

A War of Cultures
On Kobali Prime, Alliance ground forces led by Captain Harry Kim sought to break the stalemate by aiding the Kobali. An investigation into suspicious activity on the part of Kobali General Q'Nel led to the discovery that the Vaadwaur objective on Kobali Prime was not the Kobali themselves or their city, but that 'Kobali Prime' was once been a Vaadwaur colony known as 'K'Bala II' and their objective was the Kobali 'Temple' that was actually the site of a Vaadwaur stasis facility whose occupants were being used in the Kobali Rebirth process. After a series of skirmishes involving the discovery and destruction of Vaadwaur chemical weapons, the Kobali were convinced to no longer use Vaadwaur remains for Rebirth and instead preserve the bodies to be returned to the Vaadwaur when and if hostilities ended.

Failed Entaba Conference
Following a skirmish in the Shenda system; The Doctor, Neelix and an Alliance commander attended a truce conference with Gaul at a Talaxian asteroid colony in the Entaba system. The meeting would turn out to be a ruse with a number of Talaxians massacred by Vaadwaur forces and the Alliance representatives attacked. With Turei assistance, the attacking Vaadwaur were driven off.

Bluegill Discovery
During Alliance efforts to map Vaadwaur movements and locate their bases, an attempt by a Vaadwaur Overseer to capture or destroy the failed. The Overseer's increased strength and seeming invulnerability turn the Alliance to investigate the source of those abilities, leading an Alliance commander to Kartella Prime where, with Vaadwaur Commander Eldex, they discover that the Overseers are the hosts of Bluegill parasites.

Coming Together and Breaking Apart
While the Delta Alliance increases efforts to forge alliances between the Delta Quadrant species, including the Turei, Kazon, Hierarchy, Hazari, Benthans, Octanti and The Cooperative, Eldex begins making preparations to reveal Gaul's treachery and the existence of the Bluegill parasites to the Vaadwaur and the Quadrant as a whole. Aided by an Alliance commander, Eldex turns a Vaadwaur leadership meeting on Kartella Prime into a trap and is successful in showing the Vaadwaur forces the Bluegills controlling the Overseers. It is not enough, however, to end Gaul's control over the Supremacy and civil war breaks out between forces loyal to Gaul and those who choose to follow Eldex. Some Vaadwaur, however, choose to take no side and for the sake of their people's survival request aid from the Delta Alliance, seeking to start over in the Beta and Alpha Quadrants in exchange for valuable information on Vaadwaur movements.

Final Campaign
While the Alpha and Beta Quadrant races of the Delta Alliance launched a diversionary assault on Kartella Prime, the various liaisons and ranking commanders led the Delta Quadrant races on an all-out attack on Vaadwaur Prime. During the battle, Kazon forces led by Sessen would switch sides and support the Vaadwaur defenders, but would be defeated with the aid of Hirogen hunting parties, while Kazon forces led by Jal Karden would continue to support the Alliance assault. After a series of battles progressing closer to the planet, the final space battle would consist of the Alliance commanders and Eldex's forces against Gaul's flagship and support group. With destruction of his flagship, Gaul would escape to the planet's surface where he would be pursued by an Alliance commander through his command center. The Alliance ground forces would fight their way through several waves of Vaadwaur forces and Bluegill parasites until they managed to confront and defeat Gaul himself. Discovering that Gaul was acting of his own volition and not under Bluegill control, Eldex would vaporize the body in the interests of the Vaadwaur. Investigating why Gaul would return to the planet instead of attempting to escape, the Alliance commander discovered a strange device.

Mopping Up Actions
Study of the device revealed it to be a subspace communications device that would lead Alliance forces to an Elachi outpost hidden in subspace near the Nal Shadaan system. Teams from the and another ship would board the outpost to investigate further, discovering that the Bluegill parasites were actually a genetically-engineered bio-weapon. Prisoners on board the outpost would use the Alliance raid as an opportunity to make an escape attempt and while the majority died in combat with Elachi forces, former-Empress Sela of the Romulan Star Empire was recovered and revealed that the Elachi, the Solanae and also the Bluegill were all servitor races of the Iconians. Sela was taken into custody on board the Lleiset and transported back to New Romulus while the other vessel, along with the USS Rhode Island and K.D.C. Samsar, responded to a renewed Vaadwaur action against Kobali Prime.

During the Iconian War, while investigating the origins of a Krenim device in the Kyana System, the USS Chimera and another vessel would encounter a Vaadwaur patrol operating in tandem with Iconian Heralds, implying that some Vaadwaur possibly remained under Bluegill control even after Gaul's defeat.