Although the fifth Shinja Zero no Megami-sama book (Dragon Menace of Macallen) mainly concerns itself with developing the harem, it also somehow manages to squeeze in not one but two boss fights (needless to say the pacing suffers a bit from this). So quite a bit happens here, though nothing particularly surprising or alarming… beyond of course the hints that the harem will grow even further.
The second Shinigami ni Sodaterareta Shoujo book also doesn’t do anything surprising. There are no sudden left turns here and if you liked the first book there’s no reason you shouldn’t like this one as well since the structure and general content is pretty much identical.
There’s some indication the next book will be a departure however that focuses on city life and Olivia’s search for Z/her past, along with hints of possible drama revolving around Ashton (who’s background may be more complicated than he lets on).