Gun-Ota ga Mahou Sekai ni Tensei shitara, Gendai Heiki de Guntai Harem wo Tsukucchaimashita!?

軍オタが魔法世界に転生したら、現代兵器で軍隊ハーレムを作っちゃいました!?

Houta Youta, 27 years old, was a virgin, a high school dropout, and a former hikikomori. His life had been pretty horrible since his high school years and now, on his way home from work at the metalworking factory, he gets stabbed to death by a drug addict. However, it seems that he has been reborn in a fantasy world. (Source: Re:Translations)