Nightlight And Twilight Velvet have always tried to do right by others. So, when they found an orphaned colt had been left at their door, they knew right away to take him in out of the cold. How could they ever know what dangers that shadowy night would hold? After being adopted by them, Night Shadow is given all the love and care a colt of his age would need, even managing to get into Princess Celestia's School for Gifted Unicorns, the same school that his elder sister Twilight Sparkle attended. Then one day, he's given the chance to live with his sister again in her new home in Ponyville, witnessing first hand all the different adventures she and her friends go on. What is in store for this stallion, and how will he react to all the dangers that now await him?

Rewrite has been started: The Mage's Brother: Redux
https://www.fimfiction.net/story/537172/the-mages-brother-redux