Semmler got his start casting Bloodline Champions and eventually traveled to Sweden to be part of the GD Studio. Following a stint casting StarCraft II, he transitioned into casting CS:GO alongside Anders Blume for Ninjas in Pyjamas' channel, NIPGamingTV, and the two quickly made a name for themselves as the most prominent Counter-Strike casters.
In 2014, he and Anders departed NIP to found Room On Fire, and in 2016, both cast their first Overwatch tournament at the Overwatch Open, which was co-presented by ELEAGUE and FACEIT. In 2017, it was revealed that Blizzard had hired Semmler ahead of the inaugural Overwatch League season, which also meant that he would be casting OWL in Los Angeles instead of the 2018 ELEAGUE Major in Atlanta and Boston, which ran concurrently with Season 1 Stage 1.
- 2018-01-26 | Semmler on his casting career and the Overwatch League: 'Casting Overwatch does feel like coming home in a way.' by Volamel of EsportsHeaven