Dang is a common euphemism for the swear word damn, https://mashable.com/article/origin-of-swear-words - the euphemism "dang" was first used around 1780.
I believe it is also regional and somewhat archaic in use now unless you are real religious and probably also rural.
>but Asia is a pretty big place
https://en.wikipedia.org/wiki/Dang_(surname)
surname in China, Vietnam, Korea, and India.
Also apparently in Germany.