GOTHAM ACT III CONTINUES! The Batman has returned, but his city is no longer the home it once was. A sinister order now governs the shadows of Gotham. An order so precise, so methodical, that there is only one thing that could combat it. What is this one force--this singular thing that could undo order? Even if you were told, you would not believe it. In fact, you may think it's a joke.
Various is the correct author for any book with multiple unknown authors, and is acceptable for books with multiple known authors, especially if not all are known or the list is very long (over 50).
If an editor is known, however, Various is not necessary. List the name of the editor as the primary author (with role "editor"). Contributing authors' names follow it.
Note: WorldCat is an excellent resource for finding author information and contents of anthologies.