Demonology by Volkova. Gatherers of Souls

Alice Buckwheat learned from childhood that in this life, you can only rely on yourself. Immediately after school, she had to go to work to help her mother and younger sisters, and her main problem remains the search for money.... It was the promise of a good salary that led her to the house of the dark sorcerer as a personal assistant. Leon Volkova is that sorcerer. Many years ago, he barely survived and, to stay alive, got involved with forces that are better left alone. The most dangerous secrets of this world are open to Leon, and he needs an assistant like Alice: brave, stubborn, desperate, ready to do anything for money. Because what she is about to face is capable of frightening even the bravest of people.