Survival in Another World with My Mistress! (Manga) Vol. 6

IRA’S GOTTA HAVE IT!
Thanks to Ira’s genius intellect, a new technology beyond even Kousuke’s crafting powers—a golem communication device—is speedily completed! After hours of close cooperation and tinkering together, Kousuke and Ira grow comfortably closer. As the party heads toward the temporary base to test the golem com device, thousands of enemy troops muster nearby, ready to invade! Will Kousuke be able to repulse the enemy force, or will he need to call upon the golems, and Ira, for help?!
Series Overview: When Kousuke finds himself transported to a new world, he has to learn how to survive both a trackless desert and a dark forest. Luckily, his knowledge of gaming comes in handy. He has all the crafting abilities he ever wanted, and an infinitely large inventory to fill with loot and weapons! Even luckier, he meets a sexy elf princess who…snaps a slave collar around his neck and puts him to work saving the world, and servicing her every whim?!