Key said that the scar on his eyebrow was due to the accidental knocking of his eye on the edge of a flowerpot when he was playing as a child. At that time, he bled a lot and almost became blind. He then thought that the overall effect of the scar turned out pretty good so he just left it there.
Key said that when riding a bicycle when he was young, he hit a car while going downhill. His whole body flew out and after that, he didn't ride much anymore.