Ethan and Liv

Ethan Wate and Olivia Durand are two major characters in the Caster Chronicles who are first introduced to each other in Beautiful Darkness. While they don't have romantic feelings for each other, which is reinforced by the fact that they are both in committed relationships (as of Dangerous Deception), it was implied in several occasions that they've thought about it.

Meeting
Ethan Wate and Olivia Durand are introduced by Marian Ashcroft in Beautiful Darkness. The first day together, the deliver books to houses around town, and then go to Dar-ee Keen to get food. They laugh and have a good time together. Ethan often stresses the fact that Liv and Lena Duchannes are nothing alike, with Liv having blonde hair and Lena having black, Lena having green eyes and Liv having blue, and, of course, Lena being a Caster and Liv being a Mortal.

The Tunnels
Not long after they meet, Liv, Ethan and Link go on a journey together through the Caster tunnels, looking for Lena. They bond over this trip, becoming good friends. Later, right before Lena's claiming, Liv releases Macon from the Arclight he was trapped in, conscious of the fact that she will lose the status of Keeper-in-Training and put herself and Marian in jeopardy. Liv then continued to help Ethan in saving Lena, despite her obvious feelings for Ethan.

The Party
At the beginning of the school year, Savannah Snow throws a party, and Ethan invites Liv, much to Lena's dismay. During the party, using the belt that connected her and John, Ridley Casted a Furor, causing Lena and Liv to go off on each other, mockingly saying things like, "Instead of being happy that a great guy loves me, I'm going to slap on some more black nail polish and run off with some other gorgeous guy," and "Okay, little Mass I'm-Not-Here-to-Steal-Your-Boyfriend. Really, we're just friends, even though I'm smarter and blonder than the rest of you combined. And did I mention my cute little British accent?"