Calamity

“You faced your fear,” I said, digging into the next pack, comparing its items to my list. “You confronted the thing that terrified you.”
“I guess that’s one possibility,” he said. “Things did change after that. These days, being around dogs still dampens my powers, but it doesn’t completely negate them. I assumed I’d been wrong all along—I thought maybe my weakness was actually pet dander or something like that. I couldn’t experiment though, without alerting everyone to what I was doing.”
[...]
“So there’s no getting rid of the weakness for good.”
“Well, the potency of his weakness seems to have decreased over time.”
Chapter 25, Calamity, page 214