Amduscias is a demon and a powerful Grand Duke of hell with 29 Legions to his name and is the demon most connected to music with Goetia’s attributing him to bending music to his will.
His new follower has a bit of the same power.
On her right arm are the symbols for Cinder, Penetrate, and then the Sigil of Amduscias, followed by the words “Ave Satanas” on her wrist. On her left arm are the words “Music is Life”, the symbol for Sulfur, and the Sigil of Lucifer.
Her shirt says “In Nomine Dei Nostri Satanas”, a shorter version of the Latin Phrase “In nomine Dei nostri Satanas Luciferi Excelsi” (In the name of our God, Satan Lucifer of the Most High). On her stomach is “For thi is the glory.” Both are references to “Ora Pro Nobis Lucifer” by Behemoth. “Thi” is a bit of a play on words: The actual words are “For thine is the glory.” Since it leads to her thigh, I think you get the rest.