That being said, if you're looking for a male monstrous humanoid with powerful supernatural abilities, nothing comes to mind. The obvious thematic comparison would be one of the more evil and magic-y giants (they aren't all male, but males are usually the ones presented). If you're willing to consider 3e sources, the Verdant Prince from MMV seems sort of like a male hag. A number of evil fey in PF might also fit the bill (a grimstalker, perhaps).
Or you could just use the stats for a hag and say that it's male.
I'm looking specifically for sources that are open game content, whether 3.5 or PF rules specifically. I was considering having the male use the hag's basic statistics with some modifications.
Wouldn't that be the haggis?
I've seen names like "hogre" and "krampus" used to describe the mythical male hag.
In D&D that role has been filled by male giants (particularly ogres and trolls). I think you could make a good argument for either being male-only.
I think the more important question is why monsters that are traditionally shown as largely (or exclusively) male only rarely get labeled as such. When Medusa becomes a race of female monsters, why does the Minotaur become a race whose gender dynamics aren't mentioned?
In the
Puss in Boots folktale the ogre was depicted as an erudite monster that lived in luxury and could change his form. The closest equivalent in the SRD is the ogre mage, which is actually a type of fiend. How do we know that the minotaurs are always male? It's never explained how minotaurs reproduce, whereas the medusa is specifically mentioned as taking male lovers of other races with the implications therein. Although I like the idea of connecting two radically different monsters as being the sexually dimorphic sexes of the same race... maybe minotaurs or pegasi are the male counterpart to the medusa? (In mythology, Medusa was the mother of Pegasus.)
Isn't the Hag a take on the Crone, from the classic (?) Maiden / Mother / Crone triptych?
In any case, the background that I've seen for Hag makes them female, only.
Also, the notion of the hag relates to female infertility. That doesn't quite carry over to men.
The maiden/mother/crone is an invention of modern neopagans and doesn't actually appear in any ancient culture or religion, as any anthropologist worth their salt can tell you. In fact, the maiden/mother/crone dynamic is itself sexist as it implies there aren't any other roles women can fulfill besides those three.
One could write a depiction of a male hag, or krampus as I'll refer to it, that highlights the differences between the genders and uses them as a springboard for making krampus drastically different in behavior from hags. Where the hag has rejected the patriarchy that scorned her, the krampus embraces it with tongue firmly in cheek. The hag and the krampus, while fundamentally the same manner of being, hate one another with a fiery passion. A krampus, while as old and ugly as any hag (and often displaying physical mutations resembling parts of plants and animals), prefers to live in opulence and obsessive cleanliness. They claim abandoned castles in the wilderness as their lairs, adorn their homes with lavish luxuries and dress in only the finest clothes. The krampus has an insatiable sexual appetite and an endless stamina to match, as well as an truly amazing capacity for romantic self-delusion, keeping a harem of attractive young women kidnapped from nearby villages and doting on them excessively... but when their beauty starts to wane he kicks them out and sends them to the nearest village along with any children they had in the meantime. The krampus never really abandons any of his children, however, and continues to watch them from afar as they become adults... with the intent of inducting the most gifted (and invariably male) into the same dark magics he commands.
