Nahuse 
Rebuild World (Manga) Volume 6 [EPUB ebook] 

It’s Akira’s first day on the job in an underground labyrinth crawling with giant scorpions, and his supervisors just ordered him to hold the line against a fresh incursion. Not even his newly upgraded arsenal will suffice to fend off this relentless assault from all sides. His survival rests on his ability to work with two of his fellow relic hunters, the temperamental Reina and her overprotective chaperone Shiori. But Akira doesn’t work well with others at the best of times, and his last encounter with both women nearly ended in a shoot-out. Can he learn to work as part of a team and overcome the unexpected perils of his biggest job yet?