Lyric discussion by Carinapir 

Cover art for Mein Blut lyrics by Eisbrecher

The choice of which chant to use might be meaningful. They chose the Kyrie which is in Greek and is part of the Catholic mass but generally sung or said in English now.

The chant is "Kýrie eléison; Christé eléison; Kýrie eléison."

In English it means: Lord, have mercy; Christ, have mercy; Lord, have mercy.