A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
From the rules wiki: Reads, "Black Hearts, Red Blades 0G 2FV Ninja Battle: Target two of your unbowed Ninja Personalities without non-Ninja Followers: Move them home. If both of them moved, discard any cards in the current battlefield’s province and draw two cards."
My question is, what cards does this card discard? Terrains and Regions, or even up to units and armies? Or something else?
Black Hearts, Red Blades: what cards does this card discard?
Cards in Provinces (card text).
Or something else?
Yes!
Those Dynasty cards sitting in Provinces that are normally bought or ditched at the Dynasty Phase are what are discarded. Terrains, armies, units are in battlefields, not Provinces. Regions are attached to Provinces, but not in them.