I'm not sure if it was ever explained in this season or the prequel (i don't recall at all), but whatever happened to Kiyo's Answer Talker ability? Did it go away after the final battle for King? It's been so long that I completely forgot what happened to it...
He has used that in this series, and it was said it could be dormant from time to time in the original too. Apparently only Dufaux could keep it up at all times.