I'm sorry this is almost two years late, but here is my story about what would happen if Frostwing took Darkberry as his mate. For those who weren't in the RP, this is from an old RP called Faith Vs Rage RP. @Morningmist, if there's something I need to change just tell me.

Frostwing flew above the trees, thinking. He loved his mate, Faithcloud, but he loved her sister more. Even with her one short wing and her scarred buckskin coat, he loved her.

An image of Faithcloud appeared in his mind, her belly round with foal. What was he thinking? He couldn’t leave his colt and unborn foal.

But who do you want more?

Frostwing soared through a cloud, the moisture dampening his hide. He loved Darkberry more, but could he leave Faithcloud and his foals? Conflicting thoughts chased each other through his mind.

You can’t leave Snowfrost and your other foal to fend for themselves.

You can be yourself with Darkberry. You’ll never be able to do that with Faithcloud.

You’re an honorable stallion. Leaving a pregnant mare isn’t honorable.

She’ll die before spring, and then you’ll need to pick another lead mare anyway.

Frostwing gritted his teeth, flying higher. He broke through the cloud layer and narrowed his eyes against the sharp rays of the sun. I need to choose. Before Silver Herd perishes.

This was high enough. Frostwing let himself fall. He gazed at the sun, blazing in the cold, grey sky. Who will be a better lead mare?

The trees rushed towards him, and he remembered Darkberry falling through the sky. He had grabbed her wing to save her, breaking it but saving her life.

Frostwing threw out his wings, sending him rocketing forwards with his hooves skimming the trees. He lifted his nose and soared upwards. Why do I have to love two mares?

He thought of Darkberry, and his heart thudded against his ribcage. There was no going back, no pretending the connection between them didn’t exist.

He made his decision.

Frostwing found Darkberry grazing near the border. She looked up as his shadow crossed the sun, her ragged black mane falling over her neck.

Frostwing landed in front of her. “What do you want?” she asked, flaring her good wing.

Frostwing stared at the snow beneath his hooves. It was piled thickly, but he knew beneath it was delicious green shoots. How am I going to say this?

“Frostwing?” Darkberry asked.

Frostwing took a deep breath and looked at Darkberry. It’s now or never. “I was wondering- I was wondering if you would want to be my mate.”

Silence followed, and Frostwing saw Darkberry’s eyes widen. He remembered when she had fainted because he gave her a compliment, and he got ready to catch her.

Darkberry looked away. “Would- Would that mean I would be lead mare?”

Frostwing nodded. “If you want.”

A minute passed. Frostwing looked down at his hooves. Was this a mistake?

Darkberry looked back at him. “Yes,” she said. “I will.”

Frostwing threw his head up. She said yes. “Then I will announce it to the herd,” he said.

They walked back to the herd like horses, Frostwing giving Darkberry the occasional sideways glance. He could tell from the way she held her broken wing that it pained her.

“Does that hurt?” he asked her.

She shook her head, looking straight ahead.

When they reached the herd, Frostwing reared and trumpeted the call of an over-stallion. The herd gathered around them, and he saw Faithcloud in the crowd. His stomach did a flip.

When everyone had gathered, he began. “I would like to begin by congratulating Faithcloud on her devotion to the herd over the years.” Faithcloud looked puzzled, and Frostwing exhaled, ready for the hard part. “But now I have found a mare more suitable for the job. She is healthy and ready to lay down her life for the herd. She has agreed to become Silver Herd’s lead mare.” He paused for a moment. “Darkberry, come forward.”

There were gasps from the herd.

“No!”

“Faithcloud was an amazing lead mare!”

“Why are you making that dud lead mare?”

“She’ll kill our foals for fun!”

“I’d be a better lead mare than her.”

"Faithcloud was our last hope!"

Frostwing lifted his wings for silence before turning to Darkberry. “Darkberry, filly of Snowsky, you have accepted the role of lead mare. You are no longer Darkberry, single mare of Silver Herd. You are now Darkcloud, lead mare of Silver Herd.”

Darkcloud dipped her head. “I- I will try my best to protect the herd,” she said, her muscles tense.

Frostwing folded his wings, speaking to his herd. “You are dismissed.”

The pegasi flew away, muttering darkly, but one mare remained, staring at him with striking purple-brown eyes. Faithcloud.

She walked up to them, and he saw betrayal in her eyes. “How could you do this?” Her voice wavered with emotion.

Frostwing looked away. “Faithcloud, you are no longer lead mare of Silver Herd. From this day forward, you will be known as Faithpond.”

Faithpond wrapped her wings around her swollen belly. “What about Snowfrost? What about my foal?”

Frostwing sighed. Making Darkcloud lead mare was the best choice, but it still didn’t feel right. “I’m sorry,” he said, not meeting Faithpond’s eye.

Darkcloud lashed her tail. “You lose, sister.”

Faithpond stared at her, and she stared back. Frostwing watched the stand-off. Finally, Faithpond sighed and flew away.

“Faithpond!” Frostwing called after her. He leaped into the air and followed her.

He found her on an outcropping of rock, crying into her wings. Beside her was Snowfrost. “Faithpond,” he whispered, walking towards her, but she backed away.

“Please don’t talk to me,” she said. Snowfrost edged closer to his dam, staring at him with rounded eyes.

“I’m sorry,” he said, reaching out a wing.

She draped a wing over her colt. “You abandoned us.”

“I didn’t!” he cried. “You’re still part of the herd. Our- your foals are safe.” He didn’t know whether they were still regarded as his foals.

Faithpond took a shuddering breath. “If I don’t survive to look after my foals… will you take them in as your own?”

“Of course,” Frostwing promised.

Faithpond exhaled. “Thank you.” She turned and flew away, followed by Snowfrost.

Frostwing watched them, and a tear slid down his face.

The next spring, Frostwing stood next to Darkcloud. Her wing had healed nicely, and her scars from the wolf attack were gone.

He heard wingbeats, and Iceroot landed in front of him. “Frostwing,” she said, dipping her head respectfully.

Frostwing eyed the medicine mare. What had happened? “What is it?” he asked worriedly.

“It’s Faithpond, sir. She gave birth, but… she didn’t survive.”

Faithpond’s dead. The words were like a blow.

“I did everything I could,” she continued. “But the Cold Stab had weakened her. She couldn’t get through it.”

Frostwing flared his wings. “Show me.”

Iceroot led him to a cave. Frostwing peered inside. Faithpond lay on the stone floor, her wing draped over a newborn foal. The mare’s eyes were closed.

Frostwing walked inside and touched Faithpond’s shoulder. It was stone cold.

“She told me the colt’s name is Frostberry,” Iceroot said. “After her son and Darkcloud.”

Frostwing nudged Faithpond’s wing out of the way and inspected the colt. He was grey with black points and silver feathers tipped in ice blue. The colt bleated, nosing his mother as if trying to get her to stand up. When Snowberry glanced up at his father, Frostwing saw his eyes were the same purple-brown as Faithpond's, and his stomach did a flip.

Frostwing looked up at Iceroot. “Are there any mares with milk to feed him?”

“Yes, Echosong’s filly was stillborn yesterday. I’m sure she will have no objection to nursing him.”

Frostwing nodded. “Then it’s decided.” Before leaving, he took one last look at the bleating colt. Faithpond’s words rang in his mind. I will protect your foals with my life, he promised to the Ancestors. Then Frostwing turned and trotted out into the morning sun to join his mate.