My Little Pony: Fires of War

[No CP, ship whoever you like] Equestria, a harmonious home for ponies. Before the three tribes migrated to this land, it belonged to the alicorns. On a momentous day, Luna and Ita were born at the same time, and Celestia finally got her wish to become a big sister. The alicorns should have lived happily ever after, but a threat from the north soon came upon them. It was the Yellow Demon. Seeing the alicorns as a threat, he led an army of monsters to overrun the land. With their family's help, Celestia fled with Luna and Ita. By the time the Yellow Demon was defeated and the monsters disappeared, the once-prosperous Skyros had been reduced to ruins. The alicorns had all vanished, and not even their bones remained. With no one to protect them, the three alicorns could only make their home in a cave, until a wizard with a huge beard found them and recommended them as the princess and prince of Equestria. After Equestria was founded, the two princesses took charge of raising and lowering the sun and moon, while Ita led the army to expand their territory and repelled enemies who repeatedly attacked the border. But their good fortune did not last. Luna and Celestia fell into conflict, and Celestia had no choice but to banish her to the moon. Ita accused Celestia of being heartless, and they often disagreed over policy. Determined to bring Luna back, Ita began studying dark magic, and his nature began to change. The final breaking point came when Celestia decided to take military command away from Ita.