I made a little Interview with YCG the Creaters of Shovel Knight:

Have you already plans for the next DLC?

– Yes! In addition to Plague of Shadows, there will be campaigns for King Knight and Specter Knight, along with a battle mode and a body swap mode. We have a lot planned.

Is there already plans for making a sequel to you game Shovel Knight?

– We have definitely talked about it a lot, but right now, the free DLC for Shovel Knight is our focus.

Have you already some Ideas of an completly new game?

– Definitely! We always have lots of ideas for games, and are talking about them all the time. Most of our ideas are never developed into full games, but we love to brainstorm and come up with new game concepts.

Is it easy for you to create such an DLC like Plague of Shadows?

– It wasn’t easy at all, it was really difficult! To create Plague of Shadows, we had to make content around a whole game that already existed, so we had to be careful that it all fit together properly. In some ways, it was even tougher than making a standalone game!

How long did it take to plan Plague of Shadows

– We started on Plague of Shadows as soon as Shovel Knight was finished, which was about a year. However, during that time we also ported the game to many platforms, created platform-specific content, and went to lots of conventions to promote the game. Hopefully you won’t have to wait as long for the next free DLC

Thanks to Sean for Anwsering my Questions!

German Version:Here