Like Mega Man Battle Network 4 and Mega Man Battle Network 5, 6 features references to the Boktai series. Unfortunately because Boktai 3 was never released outside of Japan the Crossover sidequest and most Boktai-themed chips were removed from the international versions. In fact, all the secret chips, the Crossover Program Advance, and the entire sidequest were removed or disabled. However, the sidequest dialog is intact and even translated.