Rei really wasn't about to say which time period should know about time travel or not. After all, the others he knew were from ancient Egypt and future Ireland, respectively. Hell, he himself was from the eighties. No, what surprised him was that normal humans weren't supposed to know about time travel.

"Who told you?" Rei said sternly, narrowing his eyes. He practically hissed it. "You're not a Guardian - there are no changes on you. So one of us had to tell you. Who told you about time travel?"