Who is Adrian Ivashkov from Frostbite and what is their importance?

Adrian Ivashkov is a member of a royal Moroi family that is notorious for reckless behavior. Adrian seeks out Rose at the ski lodge and begins asking questions about Lissa while also flirting with Rose. It turns out that Adrian has the same spirit gift as Lissa and wants to talk to Lissa about it. At the same time, Adrian's feelings for Rose appear to be genuine and promise to make trouble for Rose and Dimitri in future novels in this series.