Trapped In Another World With No Magic (Mature)

(This is a mature version of my story Trapped In Another World With No Magic, which includes 18+/NSFW chapters. For the story-focused version, please check out the earlier version. Thank you!)

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Daniel is just a regular blue collar Maintenance Mechanic working for a manufacturing company. As he's winding down at home from a day of messy work repairing a CNC mill, he is surprised by a sudden glow of light beneath him. And, in an instant, his world changes. Literally.

Daniel finds himself now in the world of Zenkon, a world of fantasy beings and monsters, swords and magic, and perilous threats to the safety of the world. As if stepping into a fantasy light novel or video game, he has been apparently summoned by a sacred magic spell that requests a hero from the gods, and in reply, they sent Daniel and a young Japanese man named Rikuto. 

However, Daniel's luck doesn't seem to be good, as it's quickly discovered that, contrary to the nature of living things in the world of Zenkon, Daniel is the only one that possesses no magic or mana, making him immune to many types of magic, both beneficial and detrimental, but not protecting him from direct harm.

As such, Daniel will now have to find his way through this world using his own repair and manufacturing know-how, while Rikuto uses his own modern civics and economics knowledge to try to recover the Kingdom of Mornistae in the midst of a large scale global war.

Why were they summoned, and by what wisdom did the gods choose to send 'Divine Heroes'; one with magic and the other without, to a world of which the foundation is magic?