This Anthm rapper from LA is to not be confused with the NY based rapper that goes by ANTHM. It seems that all that separates these two is the capital letters. As far as who had the name first is anyone's guess. But to get on the point of Anthm from L.A and his music, you should check out his latest free mixtape The Dawn that is being given away as a free download. The beat drop on the title track is HUGE. Make sure you play that one really loud. Grab the entire album from bandcamp for free below.
Anthm