While Antonius still had no information about the origin of the ponies - except from the fact that they had migrated here - he certainly knew a lot more about Equestria now. Furthermore, he had the chance to acquire powerful relics for humanity's fight against Chaos.
Not bad.

He still needed a way to return to his chapter, though. Could the ponies be capable of developing warp-travel within his lifetime? He had to inquire about that:

"Please tell me, what are your greatest technological achievements within the last, say, 500 years?"

Celestia thought few seconds, then she responded:

"Well, we are using electricity now for a few decades, but mainly for lighting, to operate power tools or for entertainment purposes."

"Yes," Luna added enthusiastically,
"and I learned that lately we figured out how to store that energy in little, portable cylinders!"

"They are called 'batteries', Luna," Celestia told her.

"Speaking of batteries," Twilight interposed,
"you told us that your armor is 'active'. Do you also use batteries to power it?"

"Partly," Antonius answered,
"my armor is powered by a micro fusion reactor in my backpack. That's its main power source. There are also energy cells you could call 'batteries' as a reserve and an emergency solar collector."

"Wow, that is... Wait a moment... fusion reactor? You have a little artificial sun in your backpack?"

"More or less."

"Isn't that dangerous?"

"Not really. There are several fail-safe systems that shut the reactor down should it get damaged. In fact, I have never heard of a Space Marine who died because of a reactor malfunction."

Celestia took over the conversation again:

"That is certainly good to hear. It sounds as if you use electricity quite a lot."

"Yes, we do, as it is very versatile."

"Well, to us, it is admittedly more of a addition to our magic and not really that necessary.
Other than that, we use steam engines, and we learned how to produce plastic and rubber from mineral oil.
I think those are the most noteworthy inventions of the past few centuries. With our magic, we do not have a lot of need for new technology."

Just as Antonius had expected. Their excessive use of magic had slowed down their technological progress.

"Aha. That means that you will most probably not be able to develop warp travel within my life time," he said.

"That depends. What is your life expectancy?"

"Hmm, Chaplain Cassius is almost 400 years old and the oldest member of my chapter. I it should be about 500 years, I guess."

"You don't know how old you can get?"

Antonius raised an eyebrow.

"Not really. Space Marines usually die in battle. Dying of old age does practically not happen. That's why it's hard to give you a life expectancy."

Celestia looked a bit concerned now.

"I understand. Well, your species needed, I think it was 16,000 years from space travel to warp travel. We have not even thought about space travel yet, so no, we won't be able to help you that way. Unless you know how star ships and warp drives are built and teach us how to construct them."

What? No.
He would certainly not give human technology to aliens. Furthermore, he lacked the needed knowledge.
He had a bit of a talent for fixing machines and had gotten some lessons from the Techmarines, but it had not been enough to be sent to Mars. Especially since he had once quickly repaired a Jump Pack without the proper incense and litanies - the Techmarines were not amused.

"I am a Tactical Marine, not a Techmarine. I don't know how they work. I guess I will have to wait for the Imperium to find me, either by looking for me or even accidentally. We could, however, try to send some kind of signal once I know where this planet actually is."

"Sounds reasonable."

Now, Celestia cleared her throat and said:

"It has become late, I have to lower the sun now. You may join me, if you want to."

Witnessing her perform an impossible task would certainly be interesting. Antonius wondered what kind of show she would put on.

Everyone went outside.
The Royal Guards were waiting next to a chariot. The sun was still distinctly above the horizon, so this sun-setting-procedure would probably take quite some time.

Now, Celestia's horn lit up and the sun started accelerating towards the horizon.
Antonius was stunned.
That was impossible!
He let out a

"What the hell...?"

Celestia recognized this and paused the sunset.

"I guess sunsets work differently where you come from?"

"Yes, definitely. You really move the sun?"

"Of course I do. Look!"

The sun started moving in an eight-pattern, then it stopped again and Celestia's horn dimmed down.

The fact that this pony could actually move the sun was shocking enough, but there was something else that attracted Antonius' attention.

"Princess Celestia, could you please move the sun as soon as I tell you to?"

"Yes, I can."

Antonius quickly used his armor's cogitator to prepare a timer, then he said:

"Now."

The glowing around Celestia's horn intensified and a little more than a second later, the sun started to move.
Incredible.

"Princess, does your magic work with immediate effect?" he asked.

"Yes, it does, but why do you ask?"

The ponies really had no idea what all of this meant! Antonius had to explain it:

"Princess, we see the effect of your magic about 1.2 seconds after you cast it.
That means that your sun is just 1.2 light-seconds, or about 360,000 kilometers away from your planet! Yet, when you look at it, it has about the same visible size as the sun of Terra, which is more than 8 light-minutes away from Terra.
That means that your sun is incredibly small - even too small for a normal sun to initiate a fusion process! Not enough gravity there."

He started thinking aloud:

"Perhaps it has a super-dense core? No, the effects of the gravity would rip the planet apart.
A sun at 1.2 light-seconds and no devastating gravitational effects...
It must be something else..."

He turned to Celestia again:

"Well, Princess, I think that means that your sun can't be natural. It must be some kind of artificial fusion-torch."

Celestia looked at Antonius, speechless, eyes widened, then, she looked at the sun.
She looked back at Antonius and finally said:

"I don't know what to say. It has always been that way. I never really thought about the origin of our sun.
Be that as it may, I have to lower it now."

The sun vanished behind the horizon.

"Now, it is my time to raise the moon," Luna stated.

Her horn lit up and the moon rose above the horizon.

"Do you have solar eclipses?" Antonius asked.

"We do," answered Luna.

"Then, your moon is even smaller and closer to the planet than your sun."

"That is so fascinating!" Twilight shouted,
"...and admittedly also a bit scary. An artificial sun, similar to the one that powers your armor.
That are completely new insights! And we have not even broken the veil yet!"

"We have scheduled the breaking of the veil in two hours," Celestia announced,
"in the meantime, we can consult about everything we have learned today.
Mr. Varus, as this will just be a repetition of facts already known to you, I suggest that my guards take you on a tour through Ponyville's surroundings."

Oh, that move was too easy to see through for Antonius, Celestia had to be really troubled to do this so inelegantly. This 'repetition of facts' would be nothing short of a judgment on him.
Now, things would get serious.

That did not mean that he had to follow her plan and stick with the guards, however. He had something better to do:

"Thank you for this invitation, Princess, but I am already familiar with the surroundings. I have an idea what else I could do while you are consulting, though."

"Oh, feel free to do as you please. What are you thinking of?"

"Yesterday I met a pony who knew humans from stories and drawings. I would like to talk to her."

Celestia hesitated a little bit, then she said:

"That is a good idea."

Antonius turned to Twilight:

"Twilight, can you tell me where Lyra Heartstrings resides?"

Twilight gave him directions to Lyra's and Bob Bon's house, then the ponies and the dragon went back into the library - except for Luna.

"I will join you in a few moments," she said to the ponies.

When they were inside the library, she turned to Antonius:

"Now you know what I have done."

"Indeed."

"If you want to cancel our friendship, I would truly understand that. Considering everything your kin has experienced, you must hate me for everything I have done."

She looked down at the ground, deeply ashamed.

That was unexpected. The co-ruler of this land stood before Antonius and awaited his judgment on her? A xeno voluntarily wanted to be judged by an Astartes?

She had done nothing against mankind, but she had betrayed her own kin and got - supposedly - corrupted by Chaos. Never trust a traitor, especially if Chaos was involved!
It would, however, be a good opportunity to examine the capabilities of the Elements of Harmony: Had this exorcism worked? Was she truly reformed?
The idea of a reformed former traitor was completely new, but on this strange planet, nothing seemed to be thoroughly impossible.
He had gotten along well with her. It would be stupid to ruin that.

She was still waiting for his judgment on her.

"You won't do this again, will you?" he asked.

Luna looked up and into his eyes.

"Never," she said,
"The memories of my past sins are still haunting me. I will never repeat them."

"Then, I have no reason to cancel this friendship."

Luna started smiling again.

"Thank you, you will not regret it," she said,
"please excuse me now, the others are waiting for me. I will pick you up when it is time to break the veil."

"Good."

Luna went into the library and Antonius followed Twilight's directions to Lyra's house.
He carefully knocked on the door. A few seconds later, Bon Bon opened the door. Her eyes grew wide and she asked:

"Oh, hello Mr. Varus. I suspect you want to see Lyra?"

"Yes, if that's possible."

Bon Bon turned around and shouted:

"LYRA! Mr. Varus is here and..."

Before she had finished the sentence, Lyra was standing next to her, a giant smile on her face.

"Hello Mr. Varus! Glad you are here! You want to see the stories and drawings about humans, right?"

"Right."

"Then come in! I've already prepared everything!"

"Yes, five minutes after we have first met you..." muttered Bon Bon.

Antonius crouched and entered the house. Lyra led him into the living room. Being too heavy for the couch, he sat down next to it while she fetched the books. Finally, she and Bon Bon sat down on the couch and she opened one of the books and showed it to him.

"See? This is..." She stopped speaking and looked at the other mare.

"This is not good, you can't see anything, Bon Bon... Wait, I've got an idea!"

Having said this, she hopped down onto Antonius armored thighs.

"Lyra!" shouted Bon Bon while Antonius was at a loss for words.
Now he was a couch.

"What?" Lyra asked,
"that way, the three of us can have a look at the book together!"

She turned to Antonius:

"You don't mind, do you? Or am I too heavy?"

"No, you are not too heavy," Antonius answered.

The situation was quite unusual, but he had lived through worse things.

"Great!" Lyra said, leaned back against his armor and opened the first book. Now, Bon Bon slid to the edge of the couch next to Antonius, and everyone looked into the book.

Antonius could barely believe what he saw:
Those pictures!
Ponies, giving human children a ride.
Humans, playing with ponies.
One woman even had a young pony sitting on her lap and was giving it a... belly rub?
And the pony visibly enjoyed it?
Incredible. That was not the way you would treat an alien, that was a way you would treat... a pet!
Antonius was thoroughly confused.

The stories did not make that better; according to them, humans were almost fairytale creatures who took care of ponies!
So, that was the reason why this mare was so enthusiastic about mankind - and about him. She thought that the good nurturers of ancient times had returned - and she had a predilection for hands.

"Lyra, err... Ms. Heartstrings..." Antonius started.

"'Lyra' is fine," interrupted Lyra with a smile,
"if I may call you 'Antonius'."

"Okay, Lyra, so... are there any stories about how humans and ponies got to know each other? Or what happened to the humans?"

"Well, there is a sad story about how the humans left the ponies..."

Bingo.

"Left?" he asked.

"Yes, it is in this book over there."

She levitated the book over to them and they started reading.

The story gave him an interesting piece of information: the humans had taken care of the ponies for years, then, something happened far away and they had to leave. They boarded 'giant grey birds' and left into the sky, but not before they had 'prepared the ponies' in some way, so that they could survive on their own.

So, there had been lots of humans here. That meant, there had probably been some kind of base.
Where was that base? The story did not give any location.

"Oh, that story is so sad," Lyra said, with tears in her eyes,
"even though there are rumors that a few humans came back much later."

Antonius was all ears:

"What rumors?"

"Legend has it that some humans paid us ponies another visit. It goes on to say that Star Swirl the Bearded destroyed every story or picture of this second visit, and that those humans back then wanted it that way."

"Do you know when those stories took place?"

"No, but it must have been a really long time ago."

"How about 10,000 years?"

That was just a shot in the dark, but perhaps he was lucky.

Lyra thought about that for a bit.

"Hmm, that could be right for this dubious second visit, as I think Star Swirl lived back in that day. The first visit must have been a lot earlier, though."

So, that second visit could be related to the Great Crusade. But even if it was, why did the humans want every evidence of this visit to be erased?

No, not every evidence, just the stories and pictures, the hints at their identities and actions.
The language still spread through Equestria.
Another mystery to be solved.

Antonius was pulled from his thoughts as Lyra levitated another book over to him and said:

"In this book is my favorite story. It's about a dragon frightening ponies, and the humans scared it away! Could we please read it?"

Antonius agreed.

It was exactly as Lyra had told, a terrifying dragon, heroic humans, and a lot of cuddling at the end.
He had to think about his own experiences earlier that day: a... ahem... 'terrifying' manticore, a heroic - but not really challenged - Space Marine, and a lot of hugging.
Some things probably never changed.

Celestia was more than a bit disturbed.
First, a dangerous alien appeared in Equestria, then, she learned that there was a war of untold magnitude in the galaxy.
To make things worse, the sun, her sun, was not really a sun at all.

She almost wished that the last two days had never happened. How was she supposed to protect her ponies and their way of life now?
Well, as she had told Twilight long ago, shading the truth won't make it better.
She had to adapt to the new conditions, even if she was not fond of them.

The door to the library opened and Luna came in and sat down, smiling.
Finally.
Celestia did not really understand why her sister spend so much time with their visitor. He was dangerous, he had proven this more than once! She was worried that it was only a matter of time until he would turn against the ponies.

"Luna, I'm glad that you are here now. We must discuss what to do with Mr. Varus," she said.

"What do you mean by 'what to do' with him?" Luna asked,
"we offer him our hospitality until we find a way for him to return to his Imperium, don't we?"

"I'm not sure of this. He is a threat to every pony in Equestria."

"Oh, yeah. He could commit more thoroughly hostile acts like defeating more timberwolves or saving more ponies' lives."

"Luna, this is not a joke. You have to admit that he is dangerous."

"Sister, I am dangerous. You are dangerous. The Element Bearers are dangerous in their own way.
Antonius has not done any harm to anypony."

"I know, and I want it to stay that way. But let us say that he really will never hurt any of us, what about the Elements? He showed great interest in them."

"Of course he did. If ponykind was fighting for ten millennia and you found some artifacts that could mayhap end this war, wouldn't you try to acquire them, too?"

Celestia had to admit that this was a valid argument, but the idea of sending her dearest student and her friends into that fray was inacceptable. She sighed.

"This is a war we cannot win."

"Not on our own, at least," Luna said.

"Why are you speaking that much in his favor, Luna?"

"Don't you see it, sister? The similarities? The history of humanity is like a darker version of our history. They are not that different from us."

"They are belligerent!"

"Yes, they are. Imagine what would have happened if you hadn't been able to defeat and banish me, if I had escaped, started my own evil Nightmare-empire and constantly attacked you and your ponies.
Do you think they would still be the peaceful, friendly creatures they are now?
No, they would be like the humans - martial and used to violence. It would have been their only chance to survive.
Now that I know this, I feel more guilty than ever."

"Luna, you are not Horus!"

"No? I can't ignore the similarities! I almost did the same thing and was only stopped by the Elements of Harmony! Twice!
If we can help mankind get rid of this Chaos that tantalizes them, we simply have to!"

Celestia turned to Twilight, sure that her student would support her:

"Twilight, what do you think?"

Twilight hesitated, then she opined:

"Well, on the one hoof, I want to help Antonius and mankind, on the other hoof, I don't want to put my friends in danger.
Girls, what do you think?"

The following discussion took quite a while. The ponies and Spike talked about all the pros and cons they could think of.

Rainbow Dash was enthusiastic about helping mankind.

Applejack wanted to help Antonius, too, but was also concerned what her family would do without her.

Rarity and Pinkie Pie did not really want to go, but would join their friends at any rate, just as Spike.

The biggest surprise was Fluttershy's statement:

"I think we should go and help mankind."

What? Celestia couldn't believe her ears. Had the timid pegasus just voted for going to war?

"Fluttershy?" Twilight asked.

Fluttershy looked at her:

"You have heard what those Chaos-meanies have done. What they are still doing. I can't even start to imagine how much mankind has to suffer every day.
I know that it would mean leaving my home and most of my animal friends, but I just can't stay here, living in peace, knowing that somewhere else millions of humans die just because I do not want to help them although I possibly could.
We have to help mankind. We have to try at least."

Celestia was stunned, just as the rest of the ponies. Fluttershy was right. How could they hope to just live on as they did, knowing that they refused to help an endangered species?

"Then, it is settled," Celestia said,
"we will help Mr. Varus and mankind - if possible."

"I'm sure this is the right decision, sister," Luna opined.

"I hope so, Luna. Now, it is almost time to break the veil.
Would you please fetch Mr. Varus? In the meantime, we will head for the southern outskirts of Ponyville."

"All right, sister. By the way: Now that we have decided to help Antonius, you should probably try to get on first name terms with him. The rest of us has obviously achieved this already."

After a few stories, Antonius and the ponies heard a knock on the door and Bon Bon went to open it.
It was Luna, who wanted to pick up Antonius. She could barely contain a laugh when she saw Antonius and Lyra.

All four left the house and went to the open area south of Ponyville. The fields were crowded with ponies who wanted to get a look at the spectacle, Antonius could see Zecora and the Crusaders among them, as well as the spa ponies and almost every other pony he had seen in the last two days. They all quickly made way for him and Luna.

"Our undertaking seems to be quite an event," Antonius said quietly.

"Of course it is," confirmed Luna,
"almost every pony in Equestria will watch the sky tonight, the observatories will do that in any case. The Canterlot Royal Observatory will even take photos!"

"Very good. We can survey these photos later."

"Indeed. Furthermore, we can minimize the time in which the veil will be broken that way."

The two arrived at the top of a small hill where Celestia and the Element Bearers were waiting.
Twilight was busy aligning her telescope at the southern star.

Celestia turned to Antonius:

"Hello, Mr. Varus. I hope you found what you were looking for."

"I have, Princess Celestia, thanks for asking."

Luna stepped over to her sister's side and nudged her, apparently without reason.

Celestia darted a glance at her and continued:

"Well, Mr. Varus, just call me 'Celestia'. Would you agree with me calling you 'Antonius'?"

Oh, there was more 'befriending' going on.
Well, being on good terms with this princess would be favorable, so Antonius answered:

"Of course I agree, Celestia."

She darted another glance at her sister that was met with a satisfied smile, then she said:

"Is everypony ready? Then let us begin."

Antonius quickly put on his helmet and set his cogitator to record mode. He did not want to be completely reliant on the ponies' pictures.

"We will break the veil and have a look at the universe now!" Luna announced.

Her horn started to glow.

Everyone on the fields was absolutely silent now and watched the night sky.

It started exactly where the Southern Star was located.
The star was dimmed down and its light was looking more normal now. In its proximity, lots of other stars appeared.
As the gap in the veil grew bigger, Antonius could see that it was some kind of elongated star cluster. A short while later, the cluster described a curve and more stars of other clusters became visible.
The separate clusters were converging into another giant cluster, above and a bit to the right of the location of the Southern Star.

Now, Antonius realized what he was looking at:
This was a spiral galaxy.

The gap grew bigger and more of this galaxy was unveiled. A dirty looking, purple stain was to the left of the Southern star in a neighboring spiral arm.

That was not any spiral galaxy, it was mankind's spiral galaxy!

Antonius used his cogitator to create an overlay with a galactic map. He knew the positions of the galactic bulge and the Eye of Terror, so he could determine the position of Terra, but he already knew where it was. He created another overlay with the position of the Southern star he had recorded earlier.
It was a perfect match.

The complete galaxy was unveiled now and spanned over a large part of the night sky.

Antonius looked at it for a few seconds, then, he took off his helmet and stated solemnly:

"Truly, the light of the immortal Emperor shines upon all of his servants."

The ponies looked at him, waiting with bated breath.

"Antonius?" Luna asked,
"what is the matter? I see it is a spiral galaxy. Do you recognize it?"

"I do. This, ponies, is the galaxy of mankind. My galaxy. The purple stain you can see on the left is the Eye of Terror I told you about.
At the far right, you can see the Realm of Ultramar, home of my chapter, the Ultramarines."

"And the Southern Star? It does not only have the ability to shine through the veil, it even seems to be amplified by it.
Do you know what this star is?"

Antonius started to smile.

"Yes. You told me you use it for navigation. That is exactly its purpose, for your Southern Star, ponies, is nothing short of the Astronomican, the great beacon of mankind!"

"WOW!" Twilight shouted excitedly,
"that is incredible! But, that means we are far away from your galaxy."

"Yes," Antonius confirmed, his smile gone,
"we are deep in the intergalactic void. The Imperium will never find me here."

"Perhaps we could try to send a signal..."

"Even if you could, and even if you accomplished that this signal was only received by my people - which is quite impossible - they still could not come to pick me up.
I am just one Ultramarine. The Ultramarines do not have the resources to travel such a distance just to pick up one single Space Marine, and the rest of the Imperium will not help them."

"Why not?"

"Cost-benefit analysis. I'm not important enough."

"Oh."

The ponies looked sad now and Antonius stared at the night sky.

"My self-imposed mission failed," he mumbled quietly,
"I will never return to Macragge.
I will never fight for mankind again.
I will have to stay here until I finally die of old age.
And when the Emperor judges me in the afterlife, my accomplishments will be just pathetic, having spent most of my life unable to do my duty. An inglorious end for an Ultramarine."

"Hey!" Twilight said worriedly,
"you are not dead yet!"

Antonius knelt down and looked her in the eyes.

"For the Imperium, I am."

She stared at him, then, she suddenly flung her front legs around his neck and hugged him. The other Element Bearers joined the hug.

Luna closed the veil again, shrouding the galaxy.
Antonius took a last look at Ultramar before it vanished. The gap in the veil continued shrinking.
Before it closed completely, he could see a falling star, like a last greeting from the galaxy, then, there was just the light of the Astronomican left.

He realized that he was still being hugged by the ponies.
As if his situation was not already bad enough, he now was pitied by xenos!

"I do not need you pity," he stated.

"You don't have our pity," Fluttershy said quietly,
"but you have our compassion."

"Yeah," Applejack said,
"I know how I would feel if I couldn't see my family again!"

Antonius turned his head a bit to look at her.

"Family? I haven't seen my family in almost seven decades, they are probably all dead now."

"What? What the hay happened?"

"I joined the Ultramarines when I was ten. From then on, I lived with the chapter."

"They did not let you return home once in a while?"

"No time to 'return home'. The life of a Space Marine consists of fighting and training to fight. Such family reunions would only interfere with duty."

"Whoa, mister. You will come with me to Sweet Apple Acres, so that I can show you what a family is like and what you missed."

"An interesting offer, but I..."

"But me no buts! You will come with me. And that's that!"

Oh great. Now he was bossed around by an alien apple farmer. At least, the ponies ended the hug.

"That's not a bad idea, Applejack," Twilight opined,
"the farm is larger than the library. You could stay there for the night, Antonius. In the meantime, I will talk to Lyra. Perhaps we can find something useful in her books."

Lyra's books. The stories about humans. They would not help, unless they told him where he could find a warp-capable ship and a trained crew.
He highly doubted that.

Antonius looked at the Astronomican. He could not do his duty on this planet and he could not return.
For the first time since he had joined the Ultramarines, he had no idea what to do.
He was useless, and he would be useless for the rest of his life. That thought was disgusting.

"Well, I think it is time to say goodnight, everypony," said Celestia,
"we will invite you to Canterlot soon, Antonius. Meanwhile, you can stay in Ponyville.
I know, your situation is... somewhat less than perfect, but if you try to enjoy your stay here, you might actually start to like our peace."

Yeah, sure.

Now Luna came closer, reared up on her hind legs and hugged him.

"I'm sorry about the bad news," she whispered.

Then, she got down on all fours again and took a step back.

"Do you want to join this night's patrol again?" she asked.

Well, Antonius did not have anything better to do.

"Yes," he simply said.

"Excellent. I will pick you up at Sweet Apple Acres."

The group parted. The princesses went to their chariot and the Element Bearers - as well as the other ponies - went home.

Antonius joined Applejack and Apple Bloom on their way to the farm. As he took a look back, he could see Twilight talking to Lyra, who had a determined expression on her face. He had the strange feeling that those little aliens would really do everything they possibly could to help him.
Even if they knew they would fail, they would still try.