Lots of stories here. The first is Nymeria is kidnapped by a few griffins and minotaurs, but she is found by Celestia and Antares. Celestia corners the group in a room, shields Nymeria and the nanny who was kidnapped with her, and slaughters everyone, leaving only the leader alive but paralyzed, making him able to tell what happened and let everyone know that it's, to put it lightly, a bad idea to kidnap Celestia's daughter.

The years pass, and Nymeria joins the guard while Maia's passion is plants. She'd rather spend her time in the gardens than anywhere else. Nymeria gets in a border skirmish with some diamond dogs and dragons, and during the battle, she kills a dragon and falls off after injuring her wing. The crash snaps her horn in half, and she's almost killed by a diamond dog, but she uses the broken part of her horn to stab it in the neck. They win the battle, and she's given the name "Nymeria Hornhoof" by her fellow soldiers.

Maia is walking around Canterlot one day when she hears about a lost foal. She finds him in a park and picks him up to find his parents, but before she can do anything, she hears a twang, hiss, and finally exploding pain in her chest. She flies back and sees an arrow sticking out of her. She shakily stands up, but is hit from the other side by another arrow. Then another, then another. A group of ponies come out of the bushes, each holding crossbows. As she lays there bleeding out, one of them loads his crossbow, points it at her head and fires.

All of Equestria mourns the assassination. The alicorns work day in and day out to find the ones responsible. One of Luna's most devoted guards, one miss Comet Screech, who was never adopted and becomes a stoic soldier for Luna, blames herself, and is comforted by Antares.

The alicorns find out who assassinated Maia. It was several nobles who lost children in the war. They invite them all to a dinner at the palace under the guise of a memorial for Maia. The alicorns cage them and take them to Tartarus, where they tell the spirits there to "get creative."

The years go by, until we reach the end. The sun goes out, and, as Death told Antares in the first story, Celestia dies, and Luna soon follows. Nymeria has been dead for countless thousands of years. Kristen fades away, leaving Antares alone on a dead rock of a planet. He just wanders aimlessly for millions of years before he gathers the last tiny scrap of magic into himself and flies into space. After countless more years, he makes it to the star Antares and flies into it. He's finally reunited with his family in paradise.

Author's Note

I've retired, https://www.fimfiction.net/blog/1060252/its-time but I still feel like I should tell you how things end.