Listen to Lethe (River of Forgetfulness) or Oblivion online. Lethe (River of Forgetfulness) or Oblivion is an Unknown language song and is sung by Arne Deforce and Mika Vainio. Lethe (River of Forgetfulness) or Oblivion, from the album Hephaestus, was released in the year 2014. The duration of the song is 5:53. Download Unknown songs online from JioSaavn.