I see quite a few things here that interest me! 

Assassin x Target/Assassin
Royalty x Royalty Arranged Marriage, Childhood Friends etc.
Royalty x Servant/Trainer/Guard
Time/Dimension Traveler x Person who finds them

Medieval
Victorian
Past Times
Ancient Times China, Japan, Egypt etc.

Arranged Marriage Any time frame
Explores or Treasure Hunters on a mission
Assassination teammates

Feel free to contact me about any of the above on Discord(Jannah#1191).