Yu Ren Dong asked (a long time ago!): "Another question is about the zrf of Heroes Hexagonal Chess. As my Guard moves into the marked zone of opposite and is in face of enemy King at the same time, Guard will only promote Heroic Pawn but not Hero. I can't choose to become Hero. Is it a bug or an ambiguous rule?"
I think that I simply did not consider this possibility. The rules should clarify that the Guard promotes to a Hero in this situation, not a Heroic Pawn.
Hopefully I will have time to make this change in the ZRF sometime soon!