Complex sentence: He became one of the most prominent teen idols and rock stars in Finland in 2000s and starting 2004, the lead vocal, composer, lyricist and frontman of the Finnish glam rock band Negative.
Split into simpler sentences: He became one of the most prominent teen idols and rock stars in Finland in the 2000s. He is known as the lead vocal, composer, lyricist and frontman of the Finnish glam rock band Negative.