Dachs is a user on the civfanatics website. He is a pseudointellectual, which means he convinces people that he is very intelligent, when in actuallity he is anything but. He often goes off on "historical" rants without having any facts to support him.
There is speculation that he is actually a 11 year old boy from Malaysia, rather than an eductated adult.
In addition to being arrogant, he is also a Star Wars nerd.