Don't think that O'Falla and Kurama are a couple. I really don't want that sort of impression. They're best friends. Simple reason they are just that, O'Falla has no sexual interest in foxes and fox demons. She's a demon deer, and strong, handsome bucks have always been her thing. (Case in point.)
By the way, O'Falla is my OC. She's a really old friend of Kurama's from far back in his Youko days, expanding centuries before he was forced into the human life.
They are engaged quite a few times in sparring match to talk to each other, learn new techniques, and to keep limber their familiar skills so there's no chance their abilities will go stale, especially in the chance of a real enemy would show up with evil intentions on his/her mind.
With that being said, during this little match, they hold this conversation:
"Kurama, I don't get something. Why are you still in this form?"
"You mean the human form. (shrugs his shoulders) It's the form I took while the bounty hunters fatally shot me."
"Yeah I know, but that was over 30 years ago. They aren't after you anymore."
"I know that."
"I mean, they couldn't come after you even if they wanted to."
"I realized that, O'Falla. All the bounty hunters are dead."
"You know that, and yet you insist on maintaining this human form. It seems watered-down for someone of your stature."
"I realize it is, but I've got a marriage and kids to support."
"Who are finding their demonic wind, as I can tell. I know Shizuru accepts both sides of you. I simply miss your original self, that's all."
"You do now?"
"The great power that you had, how you made lesser demons fear you. You're not the same as you were. I even remember you saying, how did you put it?"
"You remember what, O'Falla?"
"How you completely despise the fire demon and never wanted to see his evil ugly mug in the forest of Demon World. In our territory of all places."
"Oh yeah, that was a hundred years ago since I established that. And it was an ultimatum directly to him, to his face. That feeling was mutual too. Well, he was a murderous foe on a vengeance trip and nobody needs to deal with that."
"And now is different, 31 years after your almost-demise, and you are best friends with him. So didn't see that happening."
"I know, such a swift and instant change like that. And normally I would hold to such convictions. I guess because of this human form, it makes me tolerate and even forgive people. I know if I hadn't been humanized, I would probably have not tolerated the fire demon to the grand end. Thoughts of killing him would constantly bombard my head. Trying to get rid of such a nemesis at a few points seemed like the only way."
"And yet you hesitated to destroy Hiei, which is even more odd on your part. That's not you at all to keep from killing such an enemy like that. I know you've done that on multiple occasions on our other enemies. That's mostly why a lot of lesser demons fear you. And now you've placed him in the ally category."
"Yeah, I know I've done that, perhaps to let go of the past."
"That sounds all fine and good, Kurama, but my feelings against him are still unsettling. I don't think I'll be his friend like that."