Pertaining to this particular song

Blood of the Angels

this song most have heard, recently I have shown and spoken to Sariel. Which led me to ask this what does this song mean to the names that are shown in here. I tried to get Sariel to join here, but he refuses to join. I'm not sure why.
Anyway what does the song do for you? even if your name does not show up I would still like to know, thank you.