Mathias "Vreth" Lillmåns is a Finnish heavy metal singer and songwriter who is the vocalist for the Finnish folk metal band Finntroll, and has been since 2006. He is also the vocalist and the bassist for the bands Chthonian and Twilight Moon. In 2009 he and fellow Finntroll member Samuli Ponsimaa formed the death metal band DecomposteR, in which he is the vocalist and bassist.
