Vicious (Villains, #1)

by V.E. Schwab

All Eli had to do was smile. All Victor had to do was lie. Both proved frighteningly effective.

He was not in love with Angie Knight. She didn’t belong to him.

It wasn’t just that Eli stole Angie from Victor—that was bad enough—but somehow Angie had stolen Eli from him, too. The more interesting Eli, anyway. Not the one with perfect teeth and an easy laugh, but the one beneath that was glittering and sharp, like broken glass. It was in those jagged pieces that Victor saw something he recognized. Something dangerous, and hungry. But when Eli was with Angie, it never showed.

challengers core?

Victor felt something prickle at the edge of his senses, humming. Pain. It wasn’t his.

foreshadowing guess: eli makes victor an EO thru an experimental method

It’s not like I’m actually trying to create one.” Victor’s mouth twitched, and then it twisted into a smile. “Why not?”