It kind of makes sense, given that Xichun sought the River of Immortality and Sancho was on good terms with Bari, who I'd wager knows its general location in the Underworld.
It's fucking porn, when will people like you just blacklist the tag and move on instead of whining. It's ironically amusing that people complaining about ntr gives off the exact same vibe as the cucked characters displayed in these types of hentai.
