LosCon, known as the Los Angeles Science Fantasy Society Convention to outsiders, is putting its focus this year on urban fantasy, steam-punk, science-fiction noir and, in general, the darker side of science fiction. There are a dizzying amount of events planned, including appearances by writer Emma Bull, author of “War for the Oaks,” a pioneering work of urban fantasy. Also on hand: local young-adult author Cecil Castellucci, who has lent her youthful zest to a series of books with DC Comics’ imprint, Minx. LAX Marriott, 5855 W. Century Blvd. Fri.-Sun. $25-$35 a day; $50 for the weekend. Loscon37.org.