I meant to do this a while ago, gg me.
* Kantarou was a bit of a sickly child--not exactly the sort that was prone to illness or anything to the extreme, but easily tired and not very athletic; he much preferred reading, and being ostracized by his peers as a child didn't really encourage him to be very active.
* The house is inherited from his mother--he didn't move in and start living there until after he (finally) graduated, though.
* His books sell decently well--but a lot of the money he made from that was plugged right back into his traveling and searching for the Oni-Eating Tengu, as well as a "rainy day" fund. He has not told neither Haruka nor Youko about it, though he does have a "in case of accidental death" note prepared for both of them.
* Related: his best-selling book is a collection of folktales for children. Kantarou likes kids a lot, and he's relatively good with them in the short-term. In the long-term, he's too irresponsible, but he'd make a great "take and spoil for the day" uncle.
* Kantarou has had sex with more youkai than he has with humans. (Though ultimately he hasn't had a lot either way.) He has something of a xenokink.
* He's in his mid/late thirties. Not that you can tell by looking, and while this was something he disliked when he was younger, he enjoys using it to his advantage now.
* One of the things he enjoys about is that his alcohol tolerance is somewhere through the roof--he gets relaxed and buzzed-happy, but he very rarely gets incapacitated and his hangovers are relatively mild. (That, and he cheats in drinking contests.) He thinks it's hilarious to win this sort of thing. |D
* Lying is practically second nature to him, but the more he likes you, the more honest--and at the same time, more flippant--he becomes. If he really really cares for someone, he won't lie, but he'll obfuscate like hell and hope you don't notice what he's really saying.
* Kantarou has a very strict code about what he does and doesn't allow himself to do when he's messing with their names--he has no problems with about 90% of things, but he will never force them to stay, or force them to love him. He wants them to stay because they want to, but he's just greedy and selfish enough that hecan't make himself let go yet.
* Even so, he'll release them both before he dies. Long before, if he can manage it.
* Related: the one thing that he worries about in camp is how the save system will affect the name-bond. The general idea is that if the master dies without releasing the youkai, the youkai is trapped with that name and slowly weakens over the years--but in a place where there is a way to save and revive, how does that work? :|a ... He is not particularly interested in testing it, though.
* Very little actually frightens Kantarou. Things worry him, but genuine fear isn't something he experiences very often. His only real concern about his death is whether or not he can release Haruka and Youko before then; other than that, it's just another part of life--pain means he's still alive, and he's relatively confident that he's clever enough to save his friends if it comes to that.
* He is a lot, lot, lot more powerful than canon has shown. Part of this might not be natural strength; my current pet theory is that it's connected to a) his injury from the oni, that pains him in their presence and b) how his mother died. There is something that is corrupting him in slow degrees, but increases his abilities by at least a hundredfold. (THIS IS ALL VERY MUCH SUBJECT TO CHANGE depending on what canon gives me when v11 comes out.)