@Валькирия Thank you for bringing that back to me. I remember that song from a folk music class almost 40 years ago.
"Jovano, Jovanke". (Jovana = (English) Joan). It's Macedonian singer Toše Proeski's signature tune.
http://lyricstranslate.com/en/Jovano-Jovanke-Jovano-Jovanke.html#ixzz36U4wyZmR
kill the xenos, purge the heretic!
Oh, forgot that, may the Emperor forgive me for this!
Kirill knows what's up. Right now, I think D:OS has a better OST than TW3 (obviously, we haven't heard all of the W3 songs yet though.)