The American Ninja Guild is a subsection of the Global Ninja Guilds based in America. They apparently have a strong presence in Cumberland. They are a dedicated, well trained contract assassination group who perform murder and retrieval, among a variety of other jobs, for a high price. Then again, they are some of the best available. They do not appear to have age limits, as a young Dr. McNinja was seen being already registered in the events of First Generation Ninja American.
Their leader is Dan McNinja, and apparently that one guy who doesn't wear a mask is a treasurer or something.
It is unknown if the ANG are present in the Radical Lands.