| “ | Abundant with life, this wet planet is covered in deep oceans, thick forests, and tall grasses. | „ |
| ~ Official Description |
Regnus is one of the four planets that reside within the Morgon Sector.
Topography
Similar to Baldrick Prime and Irulta.
History
Second Galactic War
Return of the Illuminate
Regnus was a peaceful planet colony of the Federation of 
Super Earth in the Southern Galactic Rim. Having been settled after the First Galactic War, its history was very uneventful. Presumably, it found enough economic success to finance the construction of more urbanized settlements at some point prior to its involvement in the ongoing Second Galactic War.
However, Regnus was not going to be allowed to live in peace for much longer. On January 2nd, 2185, the 
Illuminate attacked Regnus, following a series of raids that had been going on since the month prior.
The Helldivers, being free of any orders, would only be able to dispatch a fraction of its forces to help contain the Illuminate raiders, as they had to hold the other fronts of the war.
After 12 hours of battle, the Helldivers wouldn't be able to defeat the Illuminate raiders, who plundered all of what they could and then left.
Operation Thrice is Nice
Regnus endured several more Illuminate raids until April 2185. Like its other neighbors in the Galactic South, Regnus' highly populated colonies made it a frequent target for the Squ'ith to kidnap as many colonists as possible and ruin its prosperous infrastructure. These attacks would continue up until the defeat of the Illuminate Great Host on Super Earth, with Regnus finally seeing some sustained level of peace after the end of their raid campaign.
Following their failed takeover of Super Earth, the Illuminate retreated to the Galactic South and began formally capturing planets as opposed to their prior hit-and-run tactics. From June 2185 onwards, the xenophobic aliens would establish strongholds in the Hanzo and Omega Sectors, including the corruption of the Mega Cities on Alamak VII and Alairt III. Though the 
Helldivers were ordered to reclaim these twisted, totalitarian citadels of tyranny, they were ultimately unsuccessful as the Illuminate retained their hold on Alairt, now using it as a crucial axis point by which to spread their undemocratic tactics onto the rest of the Southern Galactic Rim.
Regnus and the rest of the Morgon Sector would go on relatively untouched until August 2185, watching as the neighboring Rictus Sector would slowly fall further into Illuminate hands. The situation would only worsen with the Illuminate's capture of the planet Valmox on July 29, which now gave them direct access into the Morgon Sector via its FTL Lines with Mog and Myrium in the Squ'ith's sights.
All in all, all 3 enemies would remain relatively quiet until late August 2185. By August 19, the Helldivers had just completed Operation Lost World in which they were able to establish the construction site of Tyranny Park 2 on Bore Rock, in addition to the liberation of Crimsica, Pandion-XXIV, and Gacrux from the 
Terminids. Following these highly successful endeavors, tyranny was about to run riot in the East. Seemingly, in response to the righteous efforts of the Helldivers, the Terminids would launch a massive, simultaneous onslaught across Erata Prime, Fenrir III, Turing, and Achernar Secundus. All Helldivers were immediately ordered to the defense against the bugs and were told to kill 6,000,000,000 Terminids to stop their onslaught from continuing.
2 days later, the Operation would hit a new wrench. The 
Automatons, who hadn't launched any assaults for a full month, joined the Terminids and launched their own brazen attack across Charon Prime, Julheim, and Mort. The Helldivers, becoming increasingly stretched, were now forced to hold on two fronts.
By August 22, the Federation of Super Earth would officially plunge into crisis. The Illuminate, becoming aware of the ongoing assaults by the Terminids and Automatons, began their own insurmountable assault upon Grafmere and Parsh. The 
S.E.A.F. were overrun, and High Command would officially declare a state of emergency across the Federation as territory was being lost rapidly. New orders were issued, and for the first time in the entirety of the Second Galactic War, the Helldivers were officially ordered to hold across all 3 fronts and kill 1,000,000,000 Illuminate combatants to stop their side of the onslaught.
Days later, the situation had officially reached its breaking point. The Terminids had taken over the 
Xenoentomology Centre on Turing and the 
Factory Hub on Achernar Secundus. The Automatons, led by their rebuilt 
Jet Brigade and 
Incineration Corps, had stomped through Curia, Fenmire, Barabos, Bekvam III, and countless other planets. In the Galactic South, the Illuminate had ravaged the entirety of the Rictus Sector save for Iro, stomped through Effluvia, and made it all the way to Seyshel Beach in the Super Earth-bordering Cancri Sector. Closer to Regnus, the Squ'ith had officially breached the Morgon Sector and taken over Myrium before the squids at the just-fallen Adhara launched a successful assault on Regnus's southern flank, Mog. It seemed the writing was on the wall for Regnus and its long-standing peace.
Sure enough, just after their takeover of Mog on August 27, the Illuminate gathered their forces and sent a massive 20 invasion fleets toward Regnus and its Mega City of Human Will.
The battle for Regnus ended up as a footnote in the long list of invasions during Operation Ultrakill. With the Helldivers stretched between multiple assaults on the Maximum Security City of Emeria by the Automatons, coupled by the loss of Tyranny Park 2 to the Terminids and multiple 
Predator Strain outbreaks in the Orion Sector, Regnus was essentially left for dead by the Corps and was left to skeleton S.E.A.F. forces to handle. Eventually, by August 29, Regnus and its lengthy time of peace was finally over. The planet was officially lost, but due to the Helldivers' success in meeting the required quota of killed Illuminate combatants, their deadly offensive would finally end there.
Operation Ad Memoriam
TLDR: Mog liberation on May 23rd left Regnus encircled. SEAF began to push the offensive. Regnus liberated by May 30th almost entirely because of SEAF lib, since basically nobody ever showed up (most people there ever were here was something around 340 Helldivers). SOMEONE WRITE THIS UP