Fragrant Grass and Setting Sun

The general Gong who wants to die to serve his country, the weak prince who has a crush on Gong, the upright and heroic enemy general, and his old friends who rebel against the barbarians. He just wants to be a knight-errant, with the world as his mat, the four seas as his home, drinking dew among flowers, and wielding a sword across the world. After all, it's not available.