In literature, the term tone refers to the writer's attitude or feelings about the subject matter as well as towards the audience. Such tone is created by authors through the use of literary elements, such as diction( defined as word choice), syntax ( or the grammatical arrangement of words), imagery ( referred to the vivid appeals to the senses); details (related with facts that are either included or omitted) and figurative language (which refers to the comparison with apparently unrelated things.
In the particular segment.. “He was tall, gaunt, with a pale skin and sunken eyes the color of a kingfisher's wing, neither blue nor green...” details and figurative languages seem to be used by the author as literary elements to express his/her attitude towards Kenny, which could be categorized as indifferent