Danny Phantom AU Clockwork's Apprentice (Audio ft Link Click) 

Danny Phantom belongs to Nickelodeon
Link Click belongs to Haoliners and LAN Studio
This is a rough idea of DP retold based on the Link Click anime series concept.
The Danny here is from another future alternate timeline in which he did not become Vlad's adopted son after the disaster of the death of his family and friends at Nasty Burger. In this timeline, he was instead taken in to become Clockwork's disciple to oversee the time stream and grew up under Clockwork's care.
One day, he found another alternate timeline in which Dan existed, causing the destruction of the world and killing everyone. This knowledge re-ignited his fear of seeing the death of his loved ones, and he wanted to change it. Clockwork had warned him many times never to change the time stream, else there would be consequences. Danny ignored his advice and kept returning to the alternate timeline to change the past. But every time Danny went back to save everyone, he kept seeing everyone die over and over again in different circumstances until he realized that he existed outside of the time stream. Danny's timeline had ceased to exist long ago (Similar to Dan's timeline in The Ultimate Enemy episode). No matter how much he tried fixing the past, his family and friends would never be revived in his present time. He could have become Dan if he had chosen Vlad instead of Clockwork as the father.
As for the ending, Clockwork saw the past timeline of Vlad's reported death in the news. Did Vlad died? Was his death tied to this Danny's original timeline? Who or what caused his death? Only Clockwork knew.