Here's what you might be thinking about:
* Black Butler manga: The manga is still being written and published, with over 160 chapters released as of today (November 2023). While it's possible that the story will come to an end eventually, there is no official end in sight.
* Black Butler anime: There have been multiple anime seasons, movies, and OVAs adapting the manga. However, none of these can be considered a "gran final" as they are only adaptations of a portion of the manga's story. The most recent anime adaptation, "Black Butler: Book of the Atlantic", was released in 2017 and left many fans hoping for a continuation. However, as of today, there's no official announcement regarding a new season.
So, if you are looking for a definitive ending to the story, you'll have to keep an eye on both the manga and anime updates for potential announcements.