MLP X Brave Frontier Crossover

In the world of Grand Gaia, a world under turmoil by Gods and Demons, numerous battles were engaged in a single war. However, none stand more important than the Six Heroes for they were warriors that influenced many others to follow in their footsteps. Each day that passed in Grand Gaia, these warriors continue to fight to protect the innocents from the Gods' wrath. As time went on, they met their end by a blade from a mysterious knight. Many were distraught from their deaths but motivation continues to keep them pushing until the war ended.

The Six Heroes having died protecting the innocent and their allies, disappear from the world, never to be seen again. However, what they discover is that their spirits have not ascended into heaven but into another world. One full of talking colorful ponies that embrace friendship. Why were they called upon this world? What purpose is there for them to be here? And are they able to return back to their home world?