Board Thread:Episode Discussion/@comment-24993958-20170114144645/@comment-4010415-20170115133214

Malcolm Neill wrote: I think they discovered dust but not really put it to use until during/after the Great Wat Nope. The opening narration of volume 1 pretty specifically states that it was mankind's use of Dust that turned the tides and stopped the Grimm from diving them into extinction. WoR: Dust says that early mankind used raw Dust and later invented guns, and it also says that raw Dust is triggered by the Aura of Humans and Faunus.

The opening narration of volume 1 even depicts people holding Dust crystals and using those crystals to shoot lightning out of their hands. As the silhouettes appear on screen, they appear in order: People using Dust to shoot lightning, people holding swords, and people holding guns. That is the evolution of mankind's combat tools.