Here is an idea from Psycho Sam:

What if between the end of the OAV and Makoto reuniting with Ifurita, Jinnai
found Ifurina (AKA: The TV Ifurita).
How would the Roshtarians react to a new Demon-God, how would Ifurita react
to haveing a "sister", and
many other things that I can't think of at the moment.

Psycho Sam