Knight's & Magic (Knights Magic)

Tsubasa Kurata is not your average citizen. Sure, he's a genius programmer and software engineer, but as far as he's concerned, his most important trait is that he's a hardcore mecha nerd. So, what happens when you take that nerd and reincarnate him into a fantastic world of swords and sorcery? Well, you'd think he'd be disappointed...but this world has magical giant robots! Obviously, Tsubasa—reborn as Ernesti Echevalier—now wants to devote his life entirely to these wondrous pieces of technology. But how exactly can young Ernie achieve his ultimate goal of getting his very own mech? He'll have to rely on his imagination, uninhibited by the common sense of this new world, as well as his extreme dedication and focus! He also might just find help in the form of a rather interesting quirk...

(Source: J-Novel Club)