It is interesting to see the relationship of Iron Hoof and Buttercup. Iron Hoof, to a degree, takes some degree of pleasure from doing what he does to those Buttercup asks him to. He respects Buttercup's wishes but still gets away with some pretty cruel things.

One may wonder if it is his frustration of not having yet become the one Buttercup values most? Perhaps he is holding out in hopes that, one day, she'll give up on this pursuit and devote her time to him? If he didn't have some sort of desire for her, Iron Hoof could have easily done away with Buttercup.

The interesting thing, if I feel this right, is that Buttercup is the dominant personality while Iron Hoof is the submissive. However, as it has been noted, it is the submissive who does tend to hold all the power.