I'm kinda bored, so:
Things You Might Not Know About Heather Since They're Only Ever Mentioned in Passing!
Heather's scarred like hell. Mostly under her clothing, but her arms and legs have their fair share too. Part of the reason she doesn't go to the onsen when anyone else is there is that she doesn't want to answer uncomfortable questions about things like how she managed to survive a round of bullets from a submachine gun (Memory of Alessa's) tearing straight through the right side of her torso. And that's just one group of scars among the dozens.
Heather's infertile because of what the god did to her insides before she got rid of it. She knows that she really should have herself checked out someday to make sure nothing that's happened to her will kill her someday, but she's afraid to ask Kabuto to do so because she at least has some idea of what he'd find (her reproductive system's been merged with her digestive tract somehow) and she doesn't want to disgust him.
She won't ever swear in the name of god unless she's in an immensely emotional state. To date, she's done it twice in the seven and a bit months she's been at camp, first in striketags when she first touched Kabuto and the love goo went into effect, and then months later without strikes after she shot the boggart that looked like her dad in the face. If she's talking about a God she'll use the word, but other than that if you've ever seen her say "Oh my god" or something it was me messing up. She doesn't have this problem with 'Jesus' or 'Heaven', but even there she's usually try to avoid them. And that's why she sometimes sound kind of old fashioned, with her "Oh my goodnesses" and everything.
She always has her bag (which is one of those big, hiking-style, backpacks) either on her back or lying somewhere near here. There're a few things that're always in it; two of her three big weapons (those being her pipe, her shotgun, and the mace Xingba gave her for Christmas) with the third being in her hand, a change of clothes or two, some cereal, jerky, and bottled water or juice, a first aid kit, her memo book, ammo, and one of those aluminum emergency blankets that fold up really tiny. Other than that, it's usually packed with various weird things that she's found lying around camp and pushed an animal over to make sure it won't do anything to her. Wandering through the Otherworld, where you never know when a walnut you find lying someplace strange will have a moonstone inside it that'll let you unlock the door to the boss, has turned her into a very odd packrat. Periodically the bag gets emptied out in her basement.
She hates her freckles, because they're arranged exactly like the burn wounds she had as Alessa. ...That one doesn't really need more explanation.
She feels guilty about not having saved Vincent from Claudia, since she knows he wouldn't have been killed if he hadn't been helping her and she'll grudgingly admit that as much as he annoyed her he never actually did anything to make her think he was that bad of a guy. And she kinds of thinks it's funny that he was stealing from the cult. But these feelings would immediately go away if she ever actually somehow found out that his real plan was 'make Heather and Claudia kill each other so my life'll be easier'.
Although she doesn't like being hurt, after spending, you know, seven years in unending agony, her pain resistance is through the roof. She can and will wander around with horrible injuries without the pain slowing her down at all.
She has a thing for broken young girls (not that way, perverts!). It's why she reaches out to characters like Anthy and River, they remind her of herself as Alessa and she wants to try to help them before they end up like she was.