sorry to say but thats all for vol 4.
although the vol 4 ch4.5 should be after vol 4 ch6.
i bought vol 4 and the extra is the last of the volume ><
i also want to see more of that couple
but in vol 4 ch. 6, the story still isn't finish right?
http://www.mangago.me/read-manga/kamisama_no_ude_no_naka/mf/v04/c006/43/
like i said, in the raw vol 4, thats all there is. the continuation is the extra (vol 4. ch4.5 uploaded here). in the extra it can be seen how they met up after sasha ran out the room to look for aya.
although it would be nice if the mangaka continued their story in the next volume ><
please update!!! the last couple's story isn't finish yet...