NIS America did not give a specific reason for the delisting, but it is most likely due to a publisher changeover. All six titles affected hold a common connection: They were originally developed or published by Kadokawa Games in Japan and by NIS America in the US and EU regions.
However, in May 2022, Kadokawa Games split up, with much of the publisher's IP and development capacity going to a new company, Dragami Games. Dragami's founder is Yoshimi Yasuda, former President and CEO of Kadokawa Games. Dragami went on to re-publish a number of former Kadokawa Games titles by itself (like
Relayer Advanced) or with new partners (like
Demon Gaze Extra).
This isn't the first time NIS America has delisted titles due to a publisher changeover. In 2020, it delisted the whole
Danganronpa series from PS Vita and PS4. The games became unavailable digitally for some time, before being re-released under Spike Chunsoft, which had recently opened international publishing operations. In other words, the games won't be gone forever.
In fact, some of them are already being sold elsewhere, under new banners.
God Wars: The Complete Legend is being sold by Dragami Games on Steam at this time.