Zack

Zack (ザック Zakku) is a young and talented smith. He considers Johann as his rival.

Zack is quite competitive and energetic. He is also very innovative and thus able to make working blueprints even from very vague discriptions by his customers.

Zack is one of the most talented smith apprentices in the entire City of Ehrenfest.

When Johann managed to beat him with their respective projects for their beruf certification, Zack's injured pride compells him to demand a meeting with Rozemyne to offer his services to her in order to take the title of Gutenberg from Johann.

Thanks to his skills he manages to gain Rozemyne's patronage and the title, though is somewhat disappointed to learn that title is not exclusive and that there are in fact multiple Gutenbergs, not just Johann.

His ability to make working blueprints out of even vague discriptions and being able to make multiple different versions to see which one will work best, his and Johann's abilities complement each other very well, since Johann is very unimaginative, resulting in him needing detailed blueprints to make anything, but is much better than Zack when it comes to finely detailed parts and precision.

Under Rozemyne's guidance the two smithes often cooperate with Zack figuring out the principles and making the blueprints, while Johann makes the high-precision parts.

Together Zack and Johann are instrumental in bringing many of Rozemyne's inventions into this world, most notably various versions of printing presses and handpumps for wells.