You decide not to argue with Cordelia, because she's right - not about the fact that you smell, but that taking a long bath or shower sounds like a really good idea after the busy day you've had. Briar's magic cleared up any actual pain or overt fatigue you were feeling after all your matches, but there was still a certain lingering sense of weariness, which has been compounded by the stress of trying to stay hidden from the unidentified sorceress, running for your life from the shadow-creature, and allure-induced headaches. All in all, you suspect that you would benefit greatly from the therapeutic power of hot water. And so you depart the arena.
The return trip to the hotel is as uneventful as a walk through Tokyo's afternoon foot traffic can hope to be - which means there's only hundreds of people crowding the sidewalks, as opposed to thousands, and the roads are only busy rather than jammed. It occurs to you that you pass more people in the few minutes it takes you to get to the hotel than you typically see in an entire day back in the 'dale; the realization is honestly kind of disturbing. Still, you deal with it well enough. You're more worried about Cordelia at first, but she doesn't seem affected at all; you can only assume that visiting LA on weekends and jetting to other parts of the world for Christmas and summer vacations past has served to acclimate her to the big cities. Lu-sensei likewise appears unmoved, while Briar stays close and quiet.
On returning to the hotel, you briefly consider indulging in some Japanese culture by visiting their indoor onsen, but you decide to give it a pass for a number of reasons - not the least of which is that you're not entirely convinced that some demon, ninja, or other weirdo isn't going to show up to issue a challenge while you're wearing a towel. A shower back in your suite serves just as well for the purpose of getting clean and relaxing, while leaving you less vulnerable to potential surprise attacks. After you're done, Cordelia disappears into the bathroom for most of an hour, while Lu-sensei - who's had an even longer day than you - withdraws to his room for a much-needed nap, advising you to wake him for dinner, preferably a late-ish one. During that time, you decide to sit down and talk to Briar about something that's been bugging you for a couple of days now.
"We didn't get an opportunity to talk about it before, Briar," you say, kicking back on a couch, "and it kind of slipped my mind with all the tournament excitement, so now that we've got a break, let's chat. Why did I hear your voice in my head the other day, and why did you get evasive when I told you about it?"
From her spot on one of the pillows, Briar sighs. "Okay, there are two things you need to keep in mind here. You're a sorcerer, and I'm a fairy."
You wait for a moment. "And?" you finally prod.
"And we kind of sort of may haveaccidentallymadeafamiliarbondwithoutmeaningto," she mumbles.
"...I'm pretty sure I heard the phrase 'familiar bond' in there," you say.
There is another vast, tiny sigh. "Yeah, you did."
"How did that happen?" you wonder. "I mean, doesn't it usually take some kind of formal ritual or contract?"
"It's a good idea to do things that way," Briar agrees, "especially if you're trying to bind something that has a mind and an agenda of its own, but all that's really necessary is an agreement between two beings that they'll support each other. You've been giving me shelter and company and a steady supply of good food, and I've been watching your back and helping you learn magic - those are some of the basic hallmarks of the classic familiar bond, natural patterns that magic could have filled and reinforced." The fairy shrugs. "You know as well as I do that magic can move on its own sometimes, especially around sorcerers, and doubly so around a sorcerer who hangs out on a mystical convergence."
You wince at that. "So the Hellmouth decided it'd be sweet to tie us together as master and familiar?"
"Nothing so conscious. It's more like you had a natural, sorcerer-ly inclination to find a familiar, while I had a natural inclination to be a kid's fairy partner, and we were both going through motions that fit the standard master/familiar mold - and then I ate a chunk of your aura to hide you from that demonic tester, forming a link that should have been temporary. The Hellmouth just screwed with it so that it hung around."
Well.
Gained familiar Briar the Fairy