Shared universes are now very popular in the west, but are there any anime and manga series that are part of shared universes, different series that are somehow connected? I know that Gundam is a massive shared universe (and predates any Marvel or DC film or television shared universes by a significant amount), although it also has numerous standalone series that are set in their own continuities, but, apart from that, I am not aware of too many other different anime/manga series that share a universe. Angel Links is set in the same universe as Outlaw Star, but, apart from Valeria and Duuz being guest stars in an episode of OS and Fred Luo making a non-speaking cameo in AL, there is no connection between them, which makes me wonder what the point was in having them be set in the same universe. What does everyone else say about this? Are there any anime and manga series that are separate but share universes?