Relations are AniDB's way of describing what anime has something to do with another and in what way; is it a sequel or prequel, is it in the same universe, have the same characters, is it a spin-off or alternate version? Anyone can add a relation for any anime, but only mods and the owners of the anime entry can remove a relation. The mere mortals needs to file a Change Requests. The different relations of an anime are listed between the rating and the AnimeNfo link in the anime details. You can also see a graph (updated according to the Routine Maintenance) of what relations an anime has by clicking the [graph] link by the relations listing.
The different types of relations are:
- Direct continuation of the story.
- Story that happens before the original.
- Same Setting
- Same universe/world/reality/timeline, completely different characters.
- Alternative Setting
- Same characters, different universe/world/reality/timeline.
- Alternative Version
- Same setting, same characters, story is told differently.
- Shares one or more characters, story is unrelated.
- Side Story
- Takes place sometime during the parent storyline.
- Parent Story
- Summarizes full story, may include additional content.
- Full Story
- Full version of the summarized story.
- Unspecified relation.
On an anime entry you can click the "Relations" link at the bottom of the page in order to add new relations to other anime. You will be taken to the "Add Relation" page.
There are three things you need to specify on this page: The title of the anime you want to add as relation, what kind of relation it is, and whether to add the matching relation to the other anime ("Chained add"). On the top of the page you see the previous relations for this anime. Specify the anime you want to add as relation by anime title, synonym title or short title in the text field. Select the type of relation you want to add. Now you have to select whether you want AniDB to automatically add the current anime to the anime you just entered as relation too. Or if for some reason you want to do it manually. If unsure always let this be checked, which is the default.
If the anime entry is not yours (you haven't created it) you can't remove relations. Please use the Change Requests forum in that case.
Why do some anime have sequel-prequel relation while others have both under the same anime entry?
This is mostly the case of post 2003 anime having 2 separate anime entries for two or more seasons of the same anime and pre 2003 entries having all under the same anime entry. The reason is simple, AniDB was created some time in 2002. New ongoing anime was added from 2003 or so. So we see the first season end and live through a considerable time difference between the last episode of season 1 and the first episode of season 2. That makes us add the second season as a separate entry, even though often times the title doesn't change, and the episode numbering continues where it left off in season 1. Furthermore, season 2 is always announced as "<anime title> Series 2" or with other similar annotation. There's no way of knowing what the anime title of the second season will be, how the episode numbering will be, that will all be known only after the first episode has aired. If the anime title remains the same in season 2 and the episode numbering will continue from season 1 (Season 1 ended with episode 13, first episode of Season 2 is numbered as 14) and especially if the OP/ED remain the same, it would be proper to only have 1 entry for both seasons. However, this will almost always be discovered quite late when it would be a lot of work to merge the 2 entries, so they're left as they are. For older (pre 2003) anime, we didn't experience any longer breaks between season 1 and 2 so there was no reason whatsoever to add them as separate entries, in fact, we often don't even notice that those anime had any breaks in scheduling to even consider a 2nd season.