"You seem like decent enough people," you say as much to catch Hiyasu's attention as to preface your question. "What's your involvement with that freak?"
Hiyasu hmms for a moment. "I'm not surprised you'd ask about him."
Gazing into his mug, the man eventually offers a solemn nod, as if confirming to himself that he's willing to have this discussion. "To make a long story a little shorter, he and I used to be good friends, back when we were in Youkai Academy. Neither of us knew anyone else there, and we shared the same class. He always struck me as of a peculiar sort, but I enjoyed his morbid sense of humor. Finding that we shared a lot of common interests, we soon were thick as thieves, and did most everything together. We joined the baseball club together, hit on girls together, got shot down together... we were practically brothers."
Taking another sip, Hiyasu then muttered, "He said more than once that he considered me to be family, more than anyone he actually shared blood with."
"Then what happened?"
Hiyasu turns to look outside, though you can tell he's watching you in his peripheral vision. "Eventually, we wound up having an eye for the same woman. While there wasn't exactly a shortage of attractive girls in those days, she was on a completely different level. Her skin was fair and soft, like freshly-fallen snow; her gaze upon me was as clear and crisp as a starry night. Of course, though we found it in ourselves to share everything else, we both were determined to have that gorgeous goddess to ourselves."
You consider this for a moment, inferring from the current situation that this woman they fought over back then was Tsurara. Confident in your reasoning, you nod for him to continue.
"Yuuda suggested, one cold winter night in our second year, that we should fight each other in our true forms. The loser would give up on chasing the girl and support the winner, but we'd remain as friends. When I saw his true face for the first time..."
Hiyasu lets out a bitter chuckle. "I won't lie, it was quite a shock to realize that the young man I'd been hanging around with the better part of two years was my ancestral enemy, but when I realized that he had a similar reaction to seeing me, I realized that nothing had truly changed; surely there was no reason we couldn't continue to be friends?"
"And then you kicked his ass?"
Hiyasu laughs, honestly amused by your choice of words. "Oh, you're damn right I kicked his ass. And true to his word, he supported me in my attempts to win Tsurara's affection. After graduation, I made him the best man at my wedding."
All trace of cheer leaves his expression, as he begins remembering what happened next. "A year or so later, when Tsurara and I realized we were finally going to have a child, we held a party to celebrate, and invited many of our friends; old schoolmates from Youkai Academy, as well as human friends that Tsurara and I had made in the years since. Though by all rights the festivities should have left me dead to the world for a day and a half, I suddenly awoke in the early hours of the morning. Save for my lovely wife sleeping beside me, the inn seemed more... quiet, somehow, than I felt it ought to. A sense of peculiar unease fell upon me, so I decided to go through the house and check on my guests."
You can see a haunted, glassy look in his eyes as he continues the story, looking almost as if he's been drinking hard liquor instead of heated chocolate milk. "I first checked the room where my parents ought to have been, and found that it was empty. The bedding wasn't even disturbed, as though they had never even set foot in the room. Unsettled, I went to the next room, and found the same scene as before. Increasingly unnerved, I went through each and every room, and continued to find them all empty and undisturbed. Finally, I went to Yuuda's room."
Hiyasu stops abruptly, a sound of shame and disgust escaping his throat involuntarily. "And when I saw the contents of that room.... when I saw the unspeakable crime that he had committed against my guests, I was so utterly repulsed that I attacked on sight. Even though I had thrown the lights on, the world around me instantly became a black void. I fought with him in that dark abyss, and when it was all said and done... at the last moment, when I remembered our friendship until that moment, I let him live. I told him to leave, and never to show himself before me again, because the next time I'd have to kill him."
....Hiyasu seems determined not to give words to whatever Terada did, but from your own encounter with him, you feel you can guess.
Hiyasu gets out of his wooden chair, goes over to the sink, and takes a moment to splash himself in the face with cold water to get himself back in the present. "Unfortunately, though he heeded my warning and kept out of Japan until now, I recently learned that he's been inflicting his depravity on other parts of the world. While I don't know the full details about his mysterious darkness-creating power, I strongly believe that it's triggered by a fight-or-flight response."
You nod. "During my encounter with him, he called it [The Abyss], and said that it's triggered by a strong emotional response."
Thinking on that, you stare at Hiyasu. No doubt he's seen some shit, but based on that story he just told you and his own reactions as he was doing so....
"You're thinking that if I go out there and pick a fight with Terada, my emotions will get the best of me and I'll fall prey to [The Abyss] again."
Holy shit, he could actually tell what you were thinking?! Usually only Mizore or your mother are able to do that!
Glancing at you out of the corner of his eye, Hiyasu chuckles. "I assumed correctly, so you don't see a need to say anything, is that it? Well, it's not surprising. I doubt there's even one sane person in the world who would still think I could do this stoically after the last few minutes."
"And that, dear husband of mine," Tsurara abruptly says from the doorway, "is why you're going to sit your cute butt back in that chair while I get started, and once we've all had a filling breakfast you're going to stay home and relax."
Rolling up the sleeves of her shirt, Tsurara then turns on the stove as she fishes some ingredients out of the freezer. "And if you try to argue with me on this," she concludes with a beaming smile, "then I'm afraid I'm going to have to freeze you solid right there, and I won't thaw you out until tonight."
Husband and Wife make eye contact and maintain it for a solid minute, before Hiyasu slumps his head in defeat. "You're too good for me," he eventually says. You can tell he's smiling, though.
....
These two.... deserve some privacy right now.
[]Go see if your mother's able to get out of bed and join everyone for breakfast.
[]What's Mizore doing right now?