Mateus tends to use people's feelings to get them to join him. He especially exploits things like fear of abandonment, people who have nowhere to go, loneliness, etc by giving them a "home"
(This is from the original story. The main character is inside baby Adra's body but it's still relevant to the new lore) Alexander wanted Adramelekh to have a more feminine name, that's why he renamed her "Solange" upon adopting her. Everyone still knows her as "Adramelekh".