The time rewinds to a few minutes ago.
"I did not expect to see a Nova Corps helmet on Earth. And looking at your armor, you have inherited the gear of a Centurion; those are the high-level leaders of the Nova Corps."
Mar-Vell looked with considerable surprise at the young man Spider-Man had brought along, who was clad in Nova equipment. He then frowned and questioned Richard Rider, "Where did you pick up this helmet, young man?"
At first, Richard had been listening with interest to this light-blue-skinned alien's rambling, but upon hearing this, his face dropped as he replied, "I didn't 'pick it up,' sir. One night while I was fixing my bike in my backyard, this helmet just flew over on its own."
Hearing this, Mar-Vell found it even harder to maintain his composure. Richard was curious and wanted to ask something else, but Mar-Vell's next sentence made him go on high alert: "Can you let me see your helmet?"
"?"
"What you said is likely true, but if it belonged to a Centurion, he would absolutely never discard his helmet without reason. Even in the entire Nova Corps, Centurions are the most elite and outstanding individuals. The entire Nova Corps consists of only five hundred members—in other words, there are only five Centurions."
The Nova, who had been wary and hesitant, became quite shocked upon hearing this. "Only five hundred people?"
"Yes, because the power of the Nova Corps is drawn entirely from the 'Worldmind,' the central computer of the planet Xandar. Such immense power cannot be mass-produced. They maintain a roster of only five hundred; every Nova is a handpicked, elite warrior with a heart of justice from across... in Earth terms, the Andromeda and Milky Way galaxies. So, it is very strange to me why a Centurion's helmet would be here."
"And more crucially, what kind of crisis could bring a Nova Corps Centurion to Earth? And a very vital point: who was he hunting, and has that person already entered Earth?"
Hearing this, Richard took off his precious helmet and handed it to Mar-Vell. Mar-Vell wasted no time and led Richard into the laboratory. Using Kree Empire technology and his knowledge of Xandar, he began to reverse-engineer the Nova helmet.
Then, the scene Peter and the others witnessed occurred: the Nova helmet, detecting the cracking program, forcibly flew onto Richard's head and began attacking the "opponent." Thus, the kid went flying haphazardly all over S.W.O.R.D. headquarters, knocking things over left and right.
Finally, he was swatted out of the sky by the Captain's shield.
"Calm down, soldier. You are the one in control of the weapon." Captain America looked at Richard, who was sprawled on the ground and seemingly unable to control himself, speaking with concern. "Control it, do not fear it. Deep breaths. Don't force it; just feel where the firing point is."
"I think Cap is trying to say 'put your finger on the trigger but don't pull,' except this helmet doesn't have a trigger."
Peter whispered a critique from behind. Tony, hearing this, nodded in agreement. "Yeah, it would be great if every weapon could be perfectly controlled just by pulling a trigger. But some guns can't even manage that; there are even bolt-action rifles called assault rifles..."
Captain ignored the banter behind him and pulled Richard up. Richard took several deep breaths before finally calming down. He took off his helmet and realized the person in front of him was actually Captain America.
"I... oh my god, it's Captain America. And Iron Man... oh my god." Richard took another deep breath. "I saw it. I saw the message left for me by the owner of this helmet. It's important! You guys have to see this!"
"Calm down, son. Let's head back to Mar-Vell's lab, and you can tell us everything."
Captain led the boy back to the lab. Mar-Vell was currently using a broom to clean up the mess. Seeing them, he hurried over. He watched as Richard placed the helmet on the table. The star emblem on the helmet projected the image of a man; he looked very similar to a human, except his skin was somewhat pinkish.
"This is Nova Corps Centurion Rhomann Dey, a famous hero of the Nova Corps. I've seen reports in war briefings about him entering combat zones to rescue civilians."
"A Kree." Rhomann Dey looked at Mar-Vell, appearing somewhat surprised. "According to my intelligence, I thought this planet had not made interstellar contact."
"I am merely a scientist here for observation, not a diplomat. And your intelligence is a bit outdated, Commander." Mar-Vell introduced Captain and Tony to the Centurion. "They are the guardians of this planet. They previously stopped a war involving a Chitauri attempt to invade their world via a man-made spatial wormhole."
The Centurion gave Captain and the others a Xandarian military salute. Although he hadn't seen it before, Captain nodded in response. At this moment, Richard asked with a hint of hope, "Are... are you still alive?"
"Regrettably, no. I am merely an artificial intelligence replicated from Rhomann Dey's thought patterns. To warn Earth of a potential threat, I came here. I was mortally wounded while wiping out a gang of space pirates. The leader of this pirate gang, Zorr, has escaped to Earth, but unfortunately, I no longer have the means to track him down."
Peter remembered Nova's origin—after all, it was identical to Green Lantern's—but he really wasn't very familiar with villains from Marvel's cosmic side. When Rhomann Dey provided an image, Peter didn't recognize who the blue, burly man was. He seemed a bit like... was he like Yondu or a Kree?
No, neither. To be honest, he looked more like Nebula? One of Nebula's kin?
"A Luphomoid. They are indeed a notorious race of pirates. What did they do that would cause a Centurion of the Nova Corps to fall in battle?"
Mar-Vell looked toward Rhomann Dey, waiting for an answer. Luphomoids were indeed troublesome, especially as pirates under Thanos, but they shouldn't have been enough to cause Xandar such heavy losses. If Thanos himself had acted, then Xandar should theoretically be out of commission.
Rhomann Dey provided a very vague answer.
"The Luphomoids found a weapon. This weapon was extremely powerful, capable of siphoning the geothermal energy of an entire planet and destroying the planet itself. The Nova Corps paid a heavy price to destroy that weapon, but the leader himself escaped to Earth."
Note: Rhomann Dey was the Nova commander on Xandar in the MCU's Guardians of the Galaxy.
The origin of Nova remains a modification for this story; this Zorr isn't actually important and is a mere extra, but he has been assigned a very interesting foreshadowing.