Fate on Fire Series by Wendy Knight

Nothing makes a new school suck worse than discovering the guy you're in love with is your prophesied nemesis. Ari is the most powerful flame-throwing sorceress ever, and her people's last hope in an ancient war. But she's also a seventeen-year-old girl, and in her free, not-hunting-nemesis times, she jumps from school to school, trying to figure out regular people her own age and pretending she'll get the chance to graduate. Shane lives a double life... moreNothing makes a new school suck worse than discovering the guy you're in love with is your prophesied nemesis. Ari is the most powerful flame-throwing sorceress ever, and her people's last hope in an ancient war. But she's also a seventeen-year-old girl, and in her free, not-hunting-nemesis times, she jumps from school to school, trying to figure out regular people her own age and pretending she'll get the chance to graduate. Shane lives a double life. He goes to school and masters the art of popularity, hiding the fact that he has a fate with a slim chance of his survival. He's destined to end a 300 year-old war by killing or being killed. He knows he's hunted by a powerful enemy who's not afraid to die. Only problem? He has no idea who that enemy is. When Ari shows up at Shane's school, angry and sullen and determined to keep him at arm's reach, neither of them realize they are supposed to be killing each other, not fall-ing in love. Until Ari does realize it, and she almost dies - by Shane's hand. less

Ari thought being in love with her prophesied nemesis sucked. But being responsible for her best friend's kidnapping? It sucks worse. Ari and Shane thought they'd beaten Fate and ended the three-hundred year war plagu-ing their people. They thought love had won. But they were so, so wrong. Instead of graduating high school like the normals, they're in a battle to save Charity - Shane's cousin, Ari's best friend, and the seer who might hold the key to ending the war for good... moreAri thought being in love with her prophesied nemesis sucked. But being responsible for her best friend's kidnapping? It sucks worse. Ari and Shane thought they'd beaten Fate and ended the three-hundred year war plagu-ing their people. They thought love had won. But they were so, so wrong. Instead of graduating high school like the normals, they're in a battle to save Charity - Shane's cousin, Ari's best friend, and the seer who might hold the key to ending the war for good. To do that, they're forced to accept help from a boy they aren't even sure they can trust. He's powerful and knows spells even Ari's never heard of, but he's also secre-tive and has a past he's determined to keep hidden . Add to that the fact that he has his sights set on Ari, and Shane would rather do without his help. Ari has bigger problems than mysterious boys and their strange powers. The powerful Edren Family is hunting her brother, and she can't very well save him or Charity while they're constantly being attacked by her own people. To stop the raids, she has to take the fight to them. But if she starts hunting the family that raised her, what kind of mon-ster will she be? Fate still waits for the death of one by the hand of the other. less