Here's a theory my mind cooked up regarding the cliffhanger ending, and Terumi's arcade, plus how Hazama and Terumi will still be involved in the next game. This has been in my head for awhile, but I never thought it had any merit until now:
Terumi and Hazama separate somehow into two bodies, and Kazuma regains his mind and gets control over the "Hazama" body, while Terumi stays as he is. Kazuma becomes the "Hazama" for the next game, while Terumi gets revived by Izanami. I don't know how exactly this would work, but there it is.