Some time had passed when Luna and her companions heard a characteristic howl.

"What was that?" asked Antonius, his bolter ready.

"Timberwolves," answered Luna,
"giant wolves, made of magically animated wood. Those creatures are quite common in the Everfree and a serious threat to ponies."

"Magical animated wood?"

There was another howl and then, three timberwolves appeared a short distance ahead of them.

"What witchcraft is this?" mumbled Antonius.

Moonlight smiled at him:

"You can go and find out, Antonius. Be our guest!"

"Affirmative."

Antonius put his bolter back to his hip and whipped out his knife.

Luna found it strange that he preferred the knife over the sword. Perhaps the sword really was just a ceremonial weapon.
Another queerness that caught her eye was the fact that he was holding the knife upside down.

He slowly walked towards the timberwolves, his left shoulder a bit advanced, the knife in his right hand almost hidden behind his back, his eyes fixed on the nearest wolf.

The first timberwolf jumped at him.
Antonius dodged to the left. His right hand shot forward and the knife severed the creature's right foreleg. The wolf faceplanted into the ground.

Luna had never seen somthing like that before. It was incredible that Antonius could move that fast, despite his size. She had no time to ponder this; the second wolf attacked and jumped.

Antonius made a quick step backwards and the timberwolf landed on the ground directly in front of him. It looked upward, clearly confused why it had missed its prey.
The creatures life was ended as the Space Marine stabbed his knife into its head, from the skullcap down to the jaw.
The light in the timberwolf's eyes faded and Antonius ripped the knife out of the creature's head - through its face - as it started to fall apart.

The third timberwolf hesitated a bit, and Luna could understand the creature. Its enemy really was a warrior unlike any Equestria had ever seen.

It finally jumped at the Space Marine.
This time, Antonius made a step forward and grabbed the creature's throat in mid flight, lifting it off the ground.
It tried to attack his arm with its claws, but it did not even leave a scratch on the armor.
With a quick movement of his right hand, Antonius reversed the knife so that its tip now pointed upward, and thrusted it into the timberwolf's chest with a crunch. The Space Marine freed his knife again as the wolf started to crumble.

Now, the first timberwolf tried to get back on its three legs, but Antonius was already next to it.
He reached down, closed his hand around the creature's throat, and lifted it into the air.

Luna had never seen a timberwolf panic before and she almost pitied the creature which's life would come to an end now.

Antonius stabbed his knife into its jaw and the weapon broke through the wolf's skullcap. The timberwolf fell apart and Antonius put his knife back to his hip and started walking back towards the ponies.

Three timberwolves killed - no, obliterated - in practically no time.
That was beyond anything Luna understood by the word 'warrior', it was more like 'force of nature'.

Suddenly, the remains of the three timberwolves started to glow in a greenish light. Antonius immediately recognized it and turned around to face them.

"More witchcraft?" he asked.

Luna quickly told him what was about to come:

"Sometimes, defeated timberwolves can reassemble into a larger creature we call 'timberwolf king'. It is very dangerous. Be careful!"

The timberwolf-parts started hovering and piecing themselves together again. More wood out of the forest joined them.

"Stand back, ponies!" shouted Antonius as he whipped out his chainsword.

Now Luna started to wonder if this weapon was perhaps not ceremonial at all.
It started making a strange, almost gurgling noise, as if lots of little explosions happened inside it.

The timberwolf king was now completely built, including a small crown on its head, and looked at the Space Marine.

Antonius raised the sword, and the gurgling became a loud and furious roar. The weapon's teeth started spinning around its blade and it emitted black smoke.

Luna realized that this was not at all a ceremonial weapon. It was in fact the most gruesome weapon she had ever seen or could imagine.
Her two guards paled as they understood how this sword worked.

The giant timberwolf came slowly closer and roared as if to challenge the roaring of the chainsword.

This was the moment Antonius sped forward incredibly fast and rammed the weapon into the timberwolf king's open maw. It erupted from the back of the creature's head, spitting out sawdust.
The wolf cried in pain, but Antonius showed it no mercy.
He pushed the chainsword through the creature's lower jaw and further down its throat. The fountain of sawdust followed the sword's path as the Space Marine cut his enemy's throat in half.
He reached the timberwolf's chest and cut deep into it, then, he yanked the chainsword out.

Before gravity could bring the body to the ground, Antonius had brought the sword to the timberwolf king's throat again and beheaded the creature which crumbled into a pile of wood, twigs and leaves.

The chainsword's roar became a gurgle again as Antonius took a step back and looked at his slain enemy. After a few seconds, he asked:

"Is this 'timberwolf king' really dead or will it piece itself together again?"

"It is definitely dead," Luna answered,
"in fact, it is even deader than I thought possible."

The chainsword became silent again as Antonius put it back to his hip and started walking towards the ponies, his armor covered with sawdust.

The guards were just standing there, mouths wide open in terrified astonishment, and Luna looked at her new friend in amazement.
This Space Marine really was more than just a warrior, even more than a force of nature, he was death incarnate.

"Done. We can resume our patrol," he simply said as he reached them.

"Err... You certainly can fight, Mr. Varus, Sir..." stammered Moonlight, clearly out of her comfort zone.

"Thank you for your compliment. These 'timberwolves' were just a minor threat, though."

The ponies just nodded and together, they continued the patrol.

Luna was deep in thought. She now was sure she had been right, neither Twilight nor her friends would be able to deal with that amount of violence. It was in fact not very easy for her either, but she knew she was probably the only pony who could do it. So, she would do it.

There was no need to fear Antonius, just because he had totally annihilated a timberwolf king without the slightest problem!

At least, she could understand her sister better now. If this Space Marine was hostile, Equestria would be in severe danger. He could probably wipe out a whole battalion of the Royal Guard with ease.

Luckily, he showed no intention of doing something like that, quite the opposite: he had accepted her friendship and had fought for them against the timberwolves.
Antonius could theoretically be a threat to her subjects, but he could be another thing, too: a great ally.

The fight against the timberwolves had gone well. Those creatures were pathetic compared to an Astartes. Even the bigger wolf...
'It is very dangerous. Be careful!'
Pffft...
It was easy to kill.

The fact that it was made of wood and had no blood was convenient, as it meant that Antonius just needed to dust his armor rather than to find another pool to clean it again.

However, it was not the only weak creature he had encountered this night.
Those guards had obviously been terrified by his performance.
What did they expect he would do? Invite the timberwolves to a cup of tea and discuss their aggressive behavior?
Nonsense. The wolves attacked him, so death was their rightful punishment.
How could guards not be used to death and violence?

Luna had been able to handle his actions a lot better than the batponies, though. Violence was definitely not new to her.
She had even shown signs of amazement. A fitting reaction to the display of the might of one of the Emperor's finest.

The remaining time of the patrol went by without further incidents and the group left the forest south-west of Sweet Apple Acres.

"After all, it was a successful night," said Moonlight, back to her normal self,
"three plus one timberwolves defeated. Usually, the fights are more exciting but less violent. I didn't even get the chance prick one of them."

Then, she turned to Antonius:

"Where did you learn to fight like that?
To be honest, I was really terrified by that sword of yours at first. Wouldn't a normal blade be enough? This spinning chain-thing is just cruel."

"Cruelty is the right punishment for the enemies of mankind," answered Antonius,
"but the main reason for the use of chainswords is their superior efficiency compared to normal blades in combat."

"So, those chainswords are your cutting-edge melee weapons?"

"No. Power-swords are even better, but less common. They use normal-looking blades but engulf them in an energy field that disrupts solid matter."

"'An energy field that disrupts solid matter'?"

Oh, of course, these ponies had no idea what that meant.
Perhaps Antonius should cease using technical terms, as it led to a lot of explaining.
On the one hand, this could be annoying, on the other hand, he had to admit he really liked talking about Astartes weaponry, so he would keep confusing the ponies with those terms and explain them afterwards:

"This field breaks up the molecular structure of the material it hits.
That means such weapons can tear through flesh, bone, stone and armor with ease."

Moonlight thought about this for a few seconds before she continued:

"You know, I always thought I was an excellent fighter with excellent weaponry.
Now I feel like a little filly playing with foam weapons. Perhaps we should do a little training fight sometime?"

What? First she had been scared of him, now she wanted to fight him as battle practice?
That was an interesting piece of information. If all ponies were like her, scaring them off wouldn't work, as they would be back sooner or later.
As for the training fight, he definitely did not want to help a xeno become a better fighter, but he couldn't say it that way, so he answered:

"The chance of you getting harmed during such a training fight is high. I would not recommend it."

This 'diplomatic behavior' was really starting to get on his nerves. He was a Space Marine, not an ambassador!

Moonlight smiled at him:

"Hmm... You're probably right. But you should never say never!"

The group had reached the fence of Sweet Apple Acres by now and Luna told her guards:

"Moonlight and Blackwing, your duty for this night is over. Well done.
You may return to the barracks now and enjoy your free time."

"Yes, Princess Luna," the two guards said as they bowed deep, then they lifted off the ground and flew off northward.

Luna turned to Antonius:

"Did you enjoy our patrol?"

"It was certainly interesting. Tell me, Luna, are there creatures more dangerous than those timberwolves?"

"Oh yes, there are hydras, for example."

Hydras. On this strange planet, every single terran legend seemed to have become true.

"Do hydras exist in your Imperium as well?" Luna continued.

"As real creatures? No, but we know them from our ancient legends."

"You know creatures of our planet from your legends?"

"Correct. Just as you know humans from your legends. An interesting conundrum."

"Indeed, yet I'm sure we will be able to fathom it."

After a short silence, Luna asked:

"Do you know any legends about us ponies? Or are there even ponies in your Imperium?"

"We have legends about pegasi and unicorns, and you could compare earth ponies to the horses which actually live in the Imperium, although those horses are much bigger, but they are just animals, not nearly as intelligent or sentient as your species apparently is."

"Err... Thank you... if it was a compliment. Anything about batponies or alicorns?"

"Nothing that I know of."

"A pity."

Another short silence followed, again broken by Luna:

"I'm curious, Antonius. What creatures do you usually fight?"

"Aliens, heretics, mutants and daemons."

"Sounds as if you are quite busy."

Antonius had to laugh.
Busy? That was a colossal euphemism!

"I don't think the term 'busy' does justice to our eternal fight against the enemies of mankind, but if you really want to phrase it like that, then yes, we are very busy."

"Your stay here has to be some kind of vacation, then."

"Vacation? I don't need vacations. They just prevent me from doing my duty as Guardian of Humanity."

"Wait a second, do you mean you never took a vacation?"

"No."

"But you must have some free time!"

"Yes, I do. Fifteen minutes each day before the rest period, at least if my company is not on a mission."

Luna looked shocked now. Antonius could not really understand why.

"You just have a quarter of an hour for yourself each day?" she asked.

"Yes, I usually use it to reflect upon my duty to the Emperor. I also read some books about ancient terra, that's why I know some of its legends."

There was a short pause before Luna spoke again:

"You live just for your duty, don't you?"

"Of course I do, just as any Space Marine does."

"And now, you can't do your duty because you are stranded here."

"Thank you for reminding me, I almost forgot that."

"I wanted to say that I understand you. I know how you feel, how I would feel. You feel useless, but I can assure you, you are not.
You are nothing less than your Imperium's ambassador in Equestria. That's an important and honorable assignment."

Important and honorable? Meh.
Diplomatic service was not really what the Emperor had in mind when he created the Astartes.

Antonius was first and foremost a warrior, with the assignment to protect mankind from its many foes.
He would not rest until humanity lived in piece in a galaxy devoid of Chaos and hostile xenos.

And then?
What if the Space Marines achieved this goal sometime?
What if there was no enemy left to fight?
Would the Adeptus Astartes just sit around, doing nothing, bored by life?
No.

Antonius was sure the Emperor, in His wisdom, had had plans what the Space Marines could do in times of peace.
His own chapter, the Ultramarines, was probably an outlook on these plans:
They were not just warriors, they were guardians of the innocent.
They did not live completely separated in the Fortress of Hera, they worked closely with the inhabitants of Ultramar.

If he developed this further...and allowed for the existence of genuinely friendly xenos...

Stop.
He was definitely thinking too much.
That was the reason why the day of a Space Marine was thoroughly planned, to prevent such strange thoughts.
Unfortunately, he could not follow this daily routine while he was on this planet, so he would - sooner or later - probably start thinking about that again, but not now.

Luna was still waiting for his reaction. Antonius sighed and finally said:

"Don't you think my diplomacy is a bit... physical?"

Luna looked at him with a baffled expression, then, she started laughing:

"Alas, this was a humorous remark!
Don't worry, though, my diplomacy is not immaculate, either.
It is good to know that you have a sense of humor."

"At least sometimes."

After a short silence, Luna asked:

"Might I ask a favor of you?"

"What do you want?"

"Could you take off that helmet and show yourself?"

Antonius looked around and checked his environment. He could not detect any sign of threats, just small rodents and insects, so he lifted his helmet and put it to his belt.

Luna's eyes grew bigger and she said:

"Fascinating. Similar, yet different."

"We are different species, but we share the structural characteristics of mammals."

"My explanation was somewhat shorter," Luna said, a challenging smile on her face.

Hmm? Was this some kind of 'friendly banter'?
Probably a ramification of this one-sided friendship.
Well, Antonius could at least try to join in.

"And less exact," he answered with a small smile of his own.

That was obviously a suitable answer, as Luna's smile grew bigger as she said:

"Antonius, I think we will get along well.
I'm afraid you will soon have to excuse me, though, as I have other duties to attend to. I suggest we head back to the library."

"Accepted."

So they went back to the library, where Luna said:

"Farewell, Antonius! It was a pleasure meeting you.
We will see again this afternoon. On that occasion, you will also meet my sister, Celestia.
See you then!"

"Farewell, Luna. It was an insightful night."

The princess took off into the sky and flew northward, in the same direction her guards had gone.

Antonius entered the library again.
It really had been an insightful night, but also a night of incomparable strangeness.
Not only that some new mysteries popped up, he also got a demi-goddess as a semi-friend.

That was definitely not the way the life of a Space Marine should go.
Antonius recapitulated his time on this planet and looked for any mistake he had possibly made. Of course, he had thought his decisions to be right or at least justified when he had made them, but perhaps he could find a violation of the Codex Astartes in retrospect.

He found none. He had perhaps 'stressed' the Codex a little bit, but he had definitely not broken it, not even when he had been forced to improvise.

His Primarch, the revered Roboute Guilliman, had simply not envisaged the situation he was in.
And Antonius could - and would - certainly not blame him. This planet was just too strange to be envisaged.

A bit disturbing was the flaw he had discovered, as it was a possible weakness.
Humanity.

Now that he thought about it - and he did not like to admit it - the behavior patterns of these aliens had some similarity to those of normal humans. Perhaps he could use his flaw to predict the ponies' reactions.

Could he turn a flaw into a perk? A weird idea, but it might work.
So, he would make use of his own humanity while keeping it under control.

Now, what was he supposed to do with the rest of the night? Ideally, something that would aid his mission.
Well, he was in a library, so there was a lot of information on various subjects waiting for him, but he knew exactly what he had to read first. He looked for the non-fiction shelf, then for 'E'.
He finally found what he had been looking for: 'The Elements of Harmony: A Reference Guide'.
He carefully pulled the book out of the shelf, went back to the central table and started reading.

Luna was happy. Her self-imposed mission to befriend their alien visitor was going better than she had thought.
She knew, finding a common feature was a very good way, but at first, she had not been sure if she could find a fitting one. They both protected their respective species, but that was more or less just their job. She had needed a common fondness or character trait.

At last, she had found one: Antonius had humor, he was sarcastic, not unlike herself. Not much, but better than nothing. She could work with that.
She had tried to change to a more lighthearted conversation and he had accepted it very well.

However, she was not too happy about meeting her sister at dawn and telling her what had happened. She could already see Celestia's scolding face before her mind's eye.
Well, some sacrifices probably had to be made.