"The Regret belongs to the mononoke," he explained, "but yes, it can be regret about what one has done. What one has not done. What was done to them. What they failed to escape. What desires have gone unfulfilled. It can be so many things, it is impossible to quantify in anything more specific than an ayakashi that has merged with human Regret."

As the oil heated over the fire, he lightly dusted the rings of onion and slices of sweet potato with flour.

"I suppose one can most easily consider it an affliction of the soul, but even that feels like an oversimplification."

Battering the veggies a few at a time, he dropped them into the bubbling cooking oil, letting them sizzle until they were a pale golden brown before scooping them out.

"...I can change the subject if you prefer. I know it is not the most pleasant topic."