A scene commission I did for Tomdepl from DA.
 
He wrote a short story to this one:  
Princess Cadance felt something disturbing in the mountains which are at the borders of the Crystal Empire. First the Princess wanted to check it out herself but her husband forbid it.
 
Because of his concern Cadance contacted her aunts and asked for their help in this matter. Since the Main Six were on a mission given to them by the map they could not assist her. Princess Celestia and Princess Luna could not simply drop their duties and go look after it. Which is why they asked Corvus to investigate this matter and keep it a secret to the subjects. Unnecessary panic should be avoided.
 
Following the wish of the royal sisters Corvus met with Princess Cadance and Shining Armor. After listening to their report they followed the instructions and directions given to him. Despite his broken horn he started to feel the presence in the mountains long before he reached it.
 
It felt strange. Like an echo of something unexplainable. While traveling through the harsh landscapes the echo became stronger. Eventually Corvus found the source of the strange magical presence. Without realizing what he was dealing with he lifted the object to insepct it. Once his magic made it float in front of him the stallion felt the darkness within it. To his horror he recognized the object as the horn of the fallen King Sombra.