I love the entire concept of the "Paintings that are real."
It sparks what could be the start of the origin of a new concept of magic or a new concept of bloodline magic or whatever. So far Beem-senpai (or whatever the painter's name is) has been limited in that his drawings are too freaky. But imagine if he could truly and utterly go all in on his paintings, and not only focus on one character, but maybe a family... living in a big mansion... that's all the way up in a snowy mountain... and he turns the painting into an entire small world, like the Painted World of Ariamis from Dark Souls 1. Or other fantasy stories that have "a world within a painting" in it.
Or if he could tone down the scariness of the paintings, he could adorn the walls with sentient paintings like in Harry Potter, and be the one to start such a magical concept.