The mirror to the world of CHS was not the only mirror portal. It was just one of many, including one to an alternate Equestria.

Celestia once made a trip in the interest of knowledge and learned something not quite what she thought she would.

And the cost was heartache.

Shipping: Celestia x Alternate Universe Sombra

Story: https://www.fimfiction.net/story/390019/always

Art: https://cdn-img.fimfiction.net/story/xcp7-1509073796-390019-medium