“Terminus,” Hazel said, “this is Percy Jackson. Percy, this is Terminus, the god of boundaries.”
“New, eh?” said the god. “Yes, probatio tablet. Fine. Ah, weapon in your pocket? Take it out! Take it out!”
Percy didn’t know how Terminus could tell, but he took out his pen.
“Quite dangerous,” Terminus said. “Leave it in the tray. Wait, where’s my assistant? Julia!”

The Son of Neptune, Chapter XIII