Lugal Gigam

Ordinary high school boy Amagi Souya was suddenly transported into another world, a fairytale world with filled with Gods, magic, magical beasts and monsters! In order to search for the mythical "Star Gate" which would bring him back home, Souya had to team up with three other "Outsiders" like himself, a samurai from the Warring Periods, a member of the NYPD with a guardian angel, a Crusader with many secrets, and explore the miasma filled ruins of the Capital City. Souya only wanted to go home, but his encounter with the Goddess Raquell, a girl self-proclaimed to be his fated lover, propelled him into a journey FULL of unforeseeable dangers!

(Source: Grimdarkz Translations)