"No Game No Life" volume 4 by Kamiya Yuu. While volumes 1-3 each had at least two games played in great detail, this one just had one game, and it's not finished. But don't be worried that this series has gone downhill as soon as the anime ended -- the volume of text that might have been allocated to game playing is instead given to new world settings and new characters, plus minor character development for Steph. The greater plot of world domination is steadily progressing.
Regarding the one game, it's a dating sim not unlike Tokimeki Memorial. Readers probably expected this event given the central theme of exploring games and the high female-to-male character ratio, what is a bit more surprising is that this dating sim is really a trap to enslave its players. Even that is merely a secondary game, the real game is two seemly cooperative races backstabbing each other. The game started out straightforward, until sudden it's a completely different game as more and more layers are revealed to the reader -- the usual meta-games that made "No Game No Life" refreshing.
This dating sim was setup by two new races, which the first half of the novel spent quite a bit of detail in explaining their background history, about how Teto's new law of nonviolence ironically drove these two race to the brink of extinction. By the end of the novel though, they can simply be summarized as "mermaids" (seemly dumb but actually quite sneaky) and "vampires" (just sneaky). Both species were trying to take advantage of the new political unbalance caused by Sora and Shiro, but as usual, Sora was sneakier than them all and had the upper hand by the end.
Sora and Shiro and their meta-games were mostly business as usual, the minor bit of character development is that Steph has actually became a fairly strong gamer, having learned from losing to Sora and Shiro all the time. In many ways, she is the main heroine for this series, and her role gains slightly more importance in each volume. With new characters appearing in every volume, hopefully the author can keep character balanced, and maybe Steph's career will become more and more rewarding.
The game with vampires and mermaids resumes in volume 5.
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Next (2014-10-24): "No Game No Life" volume 5 by Kamiya Yuu