Dead Until Evenfall

He is the prince of all Vampire clans, the son of the Count himself. He is the leader of all Werewolf packs, a fair and just First Alpha. He is the rightful heir presumptive of all Werewolves, a merciless Berserker. An eternal lifetime of rivalry and vying. Foes by nature. Brothers by soul. Lovers by heart.
All that Sehun ever longed for were a life to live, air that he could breathe, and a heart that would beat. Instead, he gets immortality and a chance to prove his worth to his father by eradicating their timeless enemy from the land which once belonged to the Vampires. When he is sent to rip the Werewolves' undying accord from within, he is obstructed by the packs' First Alpha and his brother. But he soon comprehends that he does not need to make much of an effort to annihilate the Werewolf population there. All that he has to do was to get the First Alpha's attention and the brothers to hate each other. No sane Werewolf would accept a relationship between a Vampire and Werewolf. Without a just First Alpha, the packs will be weakened and debilitated. But will Sehun be able to do the job without falling completely for the First Alpha? And will he be spared by the merciless brother who aims on ripping Sehun's head off his body from the first minute they meet?