Jace

“As his raft skimmed over the water, taking him back to the mortal world, he understood a line from the Prophecy better-an oath to keep with a final breath.
He understood how dangerous oaths could be. But Leo didn't care.
"I'm coming back for you, Calypso," he said to the night wind. "I swear it on the River Styx.”
― Rick Riordan

“Piper leaned toward [Jason], her caramel braid falling over her shoulder. Her multicolored eyes made it hard for him to think straight.
“And where is this place?” she asked.
“A . . . uh, a town called Split.”
“Split.” She smelled really good—like blooming honeysuckle.
“Um, yeah.” Jason wondered if Piper was working some sort of Aphrodite magic on him—like maybe every time he mentioned Reyna’s name, she would befuddle him so much he couldn’t think about anything but Piper. He supposed it wasn’t the worst sort of revenge.”
― Rick Riordan, The House of Hades

“We’ve arrived,” Leo announced. “Time to Split.”
Frank groaned. “Can we leave Valdez in Croatia?”
― Rick Riordan, The House of Hades

“Dalmatia,” Nico said, making Jason jump.
Holy Romulus . . . Jason wished he could put a bell around Nico di Angelo’s neck to remind him the guy was there. Nico had this disturbing habit of standing silently in the corner, blending into the shadows.”
― Rick Riordan, The House of Hades