Why did roald dahl (in his story skin) use a non-fictional character (chaim soutine) in an otherwise fictional, macabre story?

In his short story "Skin," Roald Dahl uses Chaim Soutine, a non-fictional character, to take advantage of the images already associated to the artist, thus making his fictional story much more macabre. By the time Skin was written, Soutine had already died tragically during the Second World War (he had to be constantly escaping from the Gestapo because of his Jewish origin) and, most importantly, the painter was well-known for his bizarre, misshapen human portraits and still nature paintings featuring chopped up animal meat. This association between fiction and reality successfully creates an enhanced experience of the macabre, which is built up almost inadvertently, then triggered by the story's final twist.

An informative speech that discusses how something works, carefully outlining all of the key steps from the beginning to end of a procedure, is a speech about PROCESSES.