On September 6, D3 Publisher opened a countdown page teasing the reveal of a new project, possibly related to Summon Night. As the hours went by, D3 Publisher on Twitter revealed more and more of the game's staff. Here's what we know for now, ahead of the countdown ending on September 8:

The new game project is developed by Felistella, the studio behind the Summon Night series. Technically, that was Flight-Plan, but that studio closed down in 2010, and some of its developers made Felistella then. Felistella has since then made Summon Night 5 in 2013, Summon Night 6 in 2016, and also released the Azur Lane Ps4 PC adaptation, Azur Lane: Crosswave, in 2019.

The game's scenario and world building is handled by Miyakozuki Kei, the author of the Summon Night series. The character design is by Lack, the mangaka of one of the Goblin Slayer Gaiden spinoffs, and also the chara designer of Okada Izo in FGO. PureSound, who worked on the Summon Night series and the Metal Max series, is credited for the BGM. The game's main theme is by Chiaki Fujita from rock band Sing Like Talking.

D3 Publisher is known for its IPs which mostly all started as low budget low priced games with wacky concepts like the Simple Series, Earth Defense Force, Omega Labyrinth or Bullet Girls. In particular, the OneeChanbara series got a new episode titled OneeChanbara Origin in 2019 on PS4. It looks particularly nice as it features chara design by Enami Katsumi (Baccano, Zero and Ao no Kiseki). Clouded Leopard Entertainment announced an Asia version with English subtitles in February 2020, scheduled for summer 2020 release on PS4.

D3 Publisher is also working on PS4, Switch game Earth Defense Force World Brothers, coming in Japan in 2020 and in English in early 2021. Earth Defense Force 6 is also coming in Japan in 2021 on PS4 and Switch.

Lastly, D3 Publisher also makes Otome Games, and just published a new one, Office Lovers, on Nintendo Switch:

The new game by D3 Publisher and Summon Night developers Felistella will be fully revealed on September 8, at 1700 JST. It might turn out to be a Summon Night 7 seeing the countdown has silhouettes teasing two characters, probably the male and female protagonists.