You know, I'm curious about one thing in Xenosaga.
In Episode I, Shion got an email from Kazuya, who's from Tekken. Judging by how he messages her, it seems they really are good friends, despite their opposite personalities; Shion is nice, while Kazuya is a jerk. It's as if opposites do attract.
Well, here's a good crossover challenge. Try making fanfiction stories related to them. Make it interesting.