Empress Moonbeam is Emperor Lunarlight's wife and the Empress of Equinelantis. The mother of King Solar Flare, grandmother of Princess Celestia, Princess Luna. And Great Grandmother of Sharon, Sunlight, Yuna, Snowdrop, and Moon Starlight.
Moonbeam met Lunarlight when they were at a local market place in Equinelantis, and the 2 started dating for years, and soon they were married. And later had a son whom they named Solar Flare. But sometime after Celestia and Luna were born an old Padawan to Solar Flare (Ernie) murdered Starshine and Banker Bills. The city's diamond called to her and she bonded to it and it helped defeat the evil that was before them, but she ended up staying bonded to it, where she pass away and became one with the Force.
Now, on some occasions, Moonbeam comes in Spirit form to help our heroes out and offer advice when they need it.