Wesley Chu The Art of Destiny

Once there was a prophecy that a chosen one would rise to defeat the Eternal Khan, an immortal god-king. But the prophecy was wrong. Now Jian, the former chosen hero, is just an ordinary young man trying to find his own way. But he may yet have an extraordinary destiny, because he joins forces with Taishi, his grumpy grandmaster, who instructs him in the ways of her family's powerful war art. Jian still has a long way to go before he can become her heir, so she recruits a band of elderly grandmasters who come out of retirement to whip him into shape and help with this one last job. And there are others who are also seeking their own destiny, like Qisami, an assassin on a secret mission to protect a powerful noblewoman from her enemies. But as Qisami goes undercover to complete her mission, she takes on a new identity that gives her something she never had before: friendship, found family, and new purpose. Sali also thought her fate was laid before her. She was supposed to be looking for the next Eternal Khan and now finds her clan exiled from everything she's ever known. As she leads the survivors in search of a new home, Sali discovers that she's something she never thought she could be: a leader and a revolutionary. Because sometimes destiny is grander than any prophecy can foresee. And the greatest destiny of all is the one you choose for yourself.