So I'm partaking in a DnD 5e home brew game, and in the near-ish future my male character is going to be turned into a female character without knowing and without willingness. My question is, how do I portray a character with gender dysphoria? And I suppose more importantly, how do I portray them coming to terms with their new body in a way that feels natural?
You're specifically asking about a character who experiences gender dysphoria as a result of a magical transformation later in life, as opposed to one who is born trans, so I'll suggest some ideas specific to that scenario.
Will the character come to terms with their new body?
An immediate transformation may cause physical difficulties adjusting that a character will come to terms with over time (probably determined by physical penalties in the game system), but emotionally they may or may not be able to accept the change. They might spend any amount of time and energy attempting to reverse the transformation. On the other extreme, if the character was secretly trans before they may be physically discombobulated by the suddenness of the change for a little while but emotionally overjoyed.
What does the character wear after their transformation?
A character who sees clothing, appearance, and gender as a way to control the situation (such as a politician, con artist, or performer) might immediately start wearing the type of clothes that fit their new body, with some mishaps at first as they figure out the mechanics. Some people might be happy for a little while to experiment with clothing that people would previously have thought odd.
In the (probably more likely) case that the character isn't willing to accept others perceiving them as a new gender at the drop of a hat, are they more concerned with feeling comfortable or with how others perceive them? A character who cares most about their inner feelings might keep wearing the same clothes as before. One who cares more about how others perceive them may have to experiment with clothes that better hide new bodily features. This leads into a final point.
How does the character react to people assuming their gender matches their new body?
Does the character challenge people who misgender them to a duel, kindly correct them, or ignore the situation altogether?