God and the last Demon Lord are dead, killed in the Great War between Angels, Demons and Fallen Angels. Since the end of that war, the Three Great Powers of Earth have begun their long road towards peace. To compensate for the lack of real battle experience, young devils have been competing in what is known as the Rating Game.

When Celestia gets an unexpected call, the Elements of Harmony, Spike and Princess Luna will have to face the unorthodox group led by Rias Gremory, the Crimson-haired Ruin Princess.

In a match between the peaceful, yet battle-hardened ponies and the inexperienced, but talented devil youths, who will carry the day? Who will claim the title of Strongest Little Sister, Princess Luna or Rias Gremory? And who will be stronger, a perverted teenager with a dragon sealed within him or a real life baby dragon?

High School DxD Crossover

Rated Teen for Strong Language, Mild Violence, Suggestive Themes and Mild Nudity.

Rainbow Dash attends her hometown's Millennial Summer Sun Celebration, where she meets a peculiar pink pony. When a strange portal appears during the testing of Twilight Sparkle's latest invention, and pulls their new companion inside, the two friends give chase and embark on the most important adventure in all of history.

Equestria Daily | TVTropes