Darkness Singed. Fire and Tears, #2

Nuala of Glengowyn hasn't left the elven kingdom in over a century, but not by choice. Her skills as a weapons master have made her a prisoner of her people, held apart, protected in the extreme. Until Sorcerers attack the neighboring human city. When she's sent to help the humans, however, Nuala is still far from free. Because she's forced to travel with a bodyguard, the most fearsome warrior among her people-and the only man Nuala has ever loved.
Einar is known as a battle-crazed destroyer, so feared among elves he's called by a single name: Darkness. And he has only one weakness-Nuala. Their union is forbidden, because melding their magics could destroy Nuala's gifts. But as they journey through the war-torn human city, no royal decree is a match for two hundred years of pent-up desire. Surviving the war zone won't be enough if they give in to their long denied passion.
They'll have to confront their sovereigns and face the ultimate punishment-or prove love makes them stronger.