(A/N: I learned that I was spelling 'Myrddin' wrong this entire time, so I changed it to the correct spelling. All instances where it said 'Myriddin' should be gone now. I apologize for the mistake.)
Claude and his Alliance soldiers were allowed to march only because of the former's insistence. Byleth didn't want to risk him getting hurt, but he refused to stay behind at Garreg Mach. Only about half of the Knights and Alliance soldiers marched to the Great Bridge; the remaining Knights stayed to guard Garreg Mach, and the Alliance soldiers set out to ensure that the Alliance wouldn't be attacked in Claude's absence. Among the people marching as the Resistance Army, under the flag of the Crest of Flames, was the entirety of the Golden Deer and the four members of the Blue Lions, each one acting as its own part of the army.
Byleth didn't even set foot unto the bridge before she heard the Imperial soldiers beginning their attack. Fortunately, the Knights and Alliance forces were prepared, and they went about their usual disarm-and-go strategy. Byleth tried her best to make it to Ladislava before anyone else did, but was cut short by a Knight running up to her.
"There's another army coming from the north!" He said. "It seems to be small, but they march with a tattered blue flag and wear Kingdom military uniforms. They seem to be prepared to kill."
Felix, who was close to Byleth, saw the small army in question. His frown deepened with his discontent comment, "So the mad boar and his wild animal return. Took him long enough."
Byleth didn't quite understand his statement until she realized who the small army consisted of. In the lead was Dimitri, beside him Dedue, and behind him Ingrid and Sylvain. As soon as she noticed that they were heading towards Ladislava, killing or heavily injuring most Imperial soldiers they passed, Byleth tried to reach her before they did.
She was able to intercept Dimitri before he got too close to the Imperial general. He stopped his charge for a few moments, looking at her. "Long time no see, Professor. I didn't truly believe you were still alive; it seems like I was wrong."
"Please stop killing these soldiers, Dimitri," Byleth said. "I know you bear some sort of grudge, but—"
"'Stop killing these soldiers?'" Dimitri echoed. His voice got darker as he continued, "Whose side are you on? 'These soldiers' have every right to be slaughtered. Such fools know nothing of salvation or peace; no one does!"
Byleth wasn't quite sure how to respond. Out of all the house leaders, Dimitri was the one she knew the least of. She had only heard stories of his nature, how he slaughtered Imperial soldiers. How he died trying to kill Edelgard, a person he once held some sort of respect or love for.
Finally, she thought of an answer. "Killing others isn't a good example of 'peace' and 'salvation.' But we're all people, and I agree with you that no one can truly define those two words. Some of these people don't fight willingly, though."
"The Empire is made up of vultures," Dimitri argued, his tone venomous. "They flock together to prey on the weak or the defeated, but won't hesitate to prey on each other if one of their group becomes weak or defeated. That is the state of the world—more so, it is the state of the Empire."
"Regardless, the vulture only does what it needs to survive," Byleth maintained. "These soldiers are following orders, nothing more. Please, retreat before they notice we're idly chatting."
Before Dimitri could protest, Dedue respectively said, "Perhaps it would be best to listen to the professor, Your Majesty. The Resistance Army can take care of the Imperial forces."
Dimitri still looked like he wanted to add on to the conversation, but he eventually sighed and turned to leave without a word. Dedue, Ingrid, and Sylvain followed after him. Byleth didn't wait for them to fully leave before continuing her walk towards Ladislava.
The Imperial general looked at the battle in front of her with a confused look. Her gaze was fixed on the soldiers Dimitri's group had slaughtered, comparing them to the soldiers that fought the Knights and still live.
Despite the way she oversaw the battlefield, Ladislava was on guard as soon as Byleth came up to her. "To repay Her Majesty…I will not let you pass!"
Grunting, she attacked Byleth. The same tactics the latter used and told her army to use where in play—disarm and encourage the attacker to flee—until Ladislava fell to her knees, unwillingly accepting defeat.
"Instead of taking your life, I have a request," Byleth said, taking out the letter she wrote for this occasion. "As of this moment, you are defeated and the Great Bridge of Myrddin is under Church control. Tell your soldiers to retreat; as long as you're out of sight by nightfall, the Knights will not pursue and you can prevent further casualties. This letter is written for Edelgard; make sure she receives it."
Ladislava looked at her, thinking. After a few moments, she stood, accepting the letter. "Listen up, Imperial soldiers! We can't win this battle; stop fighting and retreat!"
There was a few echoes from the Imperial army, and Byleth gave her own order: "Knights, as per agreement, do not follow them! If they're out of sight by nighttime, the Great Bridge is ours!" Echoes came from members of the Resistance Army as well as a few victorious shouts.
Both armies retreated, and Byleth sought out Dimitri's group as soon as she could. The quartet was waiting on the Alliance's side of the bridge, although Dimitri himself looked less than amused.
"You're letting an Imperial general walk away without so much as a scratch?" He asked. "My earlier question still stands."
"As does my reply," Byleth replied calmly. "But regardless, we aren't your enemies—if anything, we're allies. Strong allies, at that. Half of the former Blue Lions have come to the monastery, officially joining our cause. What stops you from doing the same?"
"Simple conflict of interests," Dimitri said. "I've heard of your philosophy, Professor, and I've heard of your return. According to the rumors, the professor of the former Black Eagles famously chose to fight against their former students. Afterwards, the battle at Garreg Mach marked the disappearance of said professor. Five years later they return to Garreg Mach, with a suddenly changed outlook.
"A former mercenary—the Ashen Demon, as some came to known them as—who had killed countless people, started to value enemy lives. They had a sort of foresight, knowing how a battle would play out before it even began. I do not agree with your values of certain lives; there are some people that deserve a fate worst than death, and who am I to know if one of those people will be spared from due punishment under your watch?"
"There will be a time when I give the order to kill," Byleth said. "But I will never give the order to kill an Imperial soldier, general, or leader, unless they are apart of the group that I believe is the cause of everything; in simplistic terms, the root of everyone's problems."
"Until you create a compromise, Professor, I won't agree to fight alongside you," Dimitri replied coldly. He turned around, and began to walk away like he had earlier.