This is my Challenge.
Make a Highschool DXD/Black Butler Story with these guidelines.
1. Sebastian is servant of either Serafall Levithan or Sona Sitri.
2. The servants (Mey Rin, Finny, Bard) have to join the same peerage or be servants of the family Sebastian is part of.
3. Ciel AND Grell HAVE TO be in this story. Could be told through flash backs if you decide to go the New Contract Route, or first meeting in the modern world..
4. Issei is jealous of Sebastian and Ciel (that whole adoparble child trope). The story can either follow cannon harem parings, or not, but NO Sebastian/Ciel.
5. Sebastian maintains his whole 'One hell of a butler" persona.
6. Sebastian has to be either a Queen or a knight if he's with Serafall.
7. Angela/Ash serves the purpose of a Evil NONFALLEN angel.
Other than that...pure creative freedom.
Surprised this hasn't been done before, but glad to be the one to get the ball rolling.