Anime Newsnetwork gives Fandom a rundown of how far anime fans can use anime characters in their own work. These feature articles' advice is subject to change when copyright law changes and are not to be used if handling a legal case.
Part 1- Found at this link explains copyright in general and creative commons licensing.
Part 2-Found at this link explains copyright when it comes to cosplay, AMV (Anime Music Videos), fanart, doujinshi, and Fansubs.
Part 3- Found at this link explains how a fan may defend themselves against copyright under a few clauses.