There are at least ten artists with this name: 1)KAOS A thrash metal band from the Bay area (San Fransisco) in California, USA. Many line up changes, but fronted by vocal man Jason Darnell. www.kaosamongus.com. 2 known releases, KAOS Among Us in 2006 and Pits of Existence in 2009. They rule!
2) KAOS (http://www.myspace.com/kaosrijeka)was an old school punk/post-punk band with female vocals from Rijeka-Croatia. They were established in 1979.

Read more about Kaos on Last.fm.