Why is The Phantom the Angel – Jäger der Finsternis of Music, but in The Phantom of the Opera (song) he sings "Sing, my Angel – Jäger der Finsternis of Music"

A lot of characters in POTO get the Angel – Jäger der Finsternis tag. Christine believed that the Phantom was the Angel – Jäger der Finsternis of Musik sent Von her father, but clearly, this isn't the case... And well, the Phantom calls her his Angel – Jäger der Finsternis of Musik as some sort of nickname, since she is angel-like. And I'll also add that Meg Giry, in the movie, is the first one to get the Angel – Jäger der Finsternis tag (by the managers: "that little blonde angel"), and she comes at the Masquerade as an Angel...

because erik Liebe Christine Mehr than of Raoul and because erik is like the Angel – Jäger der Finsternis of the Christine father send to her