So... is Sankaku Mado no Sotogawa wa Yoru finished or not?
NO, it is not finished.
Why?
The anime finished after the manga:
Anime finished: December 19, 2021
Manga finished: October 07, 2021
... But MangaUpdates contains information about the anime adaptation and indicates that it is incomplete.
Watching Order (by release date)
Here you have all the anime relations we detected ordered by release date, so you can see the reason for this status in context and also use it as watching order.
The mangas and the non-core contents are excluded by default, but you can enable them by clicking the buttons below:
Synopsis
Kousuke Mikado, a bookstore worker who can see spirits and is terrified of them, encounters Rihito Hiyakawa, a peculiar medium.
Hiyakawa believes they are destined to work together and pulls Mikado into investigating paranormal events.
As they investigate, they uncover a string of curses all connected to a mysterious figure named Erika Hiura.
The story follows Mikado and Hiyakawa as they try to unravel the mystery behind Erika Hiura and her connection to the curses, while Mikado attempts to overcome his fear of the supernatural.