Sirenia formed only a few years ago after leader Morten Veland left his former band
Tristania over creative differences. From what I can tell, Tristania wanted to go more gothic, and Veland wanted to continue in the direction of Tristania's first two records
Widow's Weeds and
Beyond the Veil. Actually I'm quite happy with this split, as Tristania's last record
World of Glass was very good and both of Sirenia's records are amazing.
Sirenia combine gothic metal with Veland's black metal screeches and very epic productions with a choral group and multiple solo singers. The female voice in Sirenia differs greatly from Tristania's, being much more how can I say.. willowy. They even use the current male vocalist from Tristania on a few songs on their newest cd An Elixir of Existence. His very deep gothic rock voice works perfectly with the songs he is used on.
Again and again with every song on each Sirenia cd Veland proves himself to be a master at his style of music. Sirenia is a great band, where every moment is really very epic and very touching. I highly suggest checking out their music.
Discography
At Sixes and Sevens 2002
An Elixir of Existence 2004