My Big Sister Lives in a Fantasy World: Volume 5

Between a secret battle to reassemble a dismembered evil god and a threat from destiny-altering beings waiting in the wings, the world's strongest little brother seems to have enough on his mind. But there's even more waiting in store for Yuichi Sakaki, and things are about to get more chaotic by the week. Soon, a yakuza gang is stalking his little sister, a demon doll is stalking Aiko, an overzealous archer is stalking him... and that's only the beginning!

[From J-Novel Club]