The late-90s were an interesting time for anime. This wasn’t an era when everything that was airing and all that came before it were bad. This was near the end of a period in Japan that would be called The Lost Decade due to economic stagnation. The animation industry, which by its own standards doesn’t have a lot of money, had even less money flowing around than normal.
By the summer of 1999, the selection of anime currently airing was in a strange state. Generally there were three different types of shows; the types of child-friendly series that celebrated cultural traditions, a 2nd type that was the exact opposite in celebrating sex and debauchery (eroge adaptations were now a thing) and finally a third group that was really about adapting to what the world had become. The Legend of Black Heaven definitely fits in to the latter category.