>>101436163OTGW IS explicitly based in The Divine Comedy and most part of the structure of the story itself is based in scenes of the divine comedy, the relationships between Wirt and Beatrice is directly based in the Divine Comedy's characters and Greg is named after Virgil, being Gregory a translation of the name Virgil, yeah even the meaning of their names is applied to the characters. The Unknown is based directly in the Hell and The Beast is Lucifer lord of the hell, they can leave the unknown when the Beast is killed just like Dante and Virgil can leave the Hell when they defeat to Devil.
Sara was included in the story because there is a new tendency in the entertainment industry where the networks try to attract to a certain sector of population (the dark skinned people) by include dark skinned characters in the stories, mostly as romantic interests of other characters. I have heard people saying that Sara is based in a certain woman mentioned in the divine comedy to whom Dante writes poetry trying to "deny his feelings for Beatrice" but I think that Sara was included following the aforementioned tendency.
There are many stories based in the Divine Comedy but the character interpreting to Beatrice is always white skinned with a hair in a red tone respecting part of the description of the character, Beatrice can't be black and that's why Sara exist in OTGW.