The Dandadan manga is indeed new. It has entered the manga scene recently and has managed to make a mark with its fresh concepts and engaging characters.
First, understand the basic principles of light and shadow. Then, study how manga artists use different tones and gradients. Pay attention to the direction of the light and the shape of the objects. It's all about experimentation and building your skills over time.
I recommend a novel called South of Qingqiu. It's a fantasy romance novel about ancient myths. Although it's not a manga, it's quite similar to the manga plot you mentioned. The novel was about a healing story. There were all kinds of stupid and cute monsters accompanying her. The female protagonist could see the monsters and inherit the healing ability. I hope you like my recommendation, Mwah ~😗