For a time, there was some remote hope that Bluehole (now Krafton) would do something with the Devilian franchise (since it remained listed as one of the games that Bluehole offered). Bluehole obviously had turned down lowball offers by asset flipping publishers (given the sort of cash grabs that have happened with other titles in 2018) since the TERA derived intellectual property was something they didn’t want to just have re-published by anyone.
It was also becoming clear that Bluehole did not want to invest resources to technically support it in the event that another major publisher would be interested in actually re-publishing it.
With the recent corporate reorganization and subsequent changes made for the Bluehole Alliance (now KRAFTON Game Union), that listing of Devilian has been completely removed (the only remaining references that it ever existed are in the yearly news highlights on the Krafton site). While it is still listed on the english site, that is only because they rarely update that portion.
IMHO, this pretty much closes the book on the franchise.
