Kuroshitsuji, 91 Days Recommendations
Both are set in the 1900s in European countries. Both of the main characters are seeking revenge on the people who killed their family. Both stories are dark.
revenge type issue and the both are good mysteries.
Ones british, ones american, around the same time line, similar plot, i guess. Both basically contain an MC wanting revenge on a group of people they need to learn the identities of after loosing their parents on their birthdays.