Briefly about Song Of The Sky Walkers manga:
In the midst of an auspicious sign from the heavens, the emperor’s family gave birth to a special pair of twins—a male born with a forehead mole the colour of cinnabar, and a female born with six fingers. However, this brother and sister pair is cruelly separated by fate! One is taken eastward to celestial Penglai, to embark on the long road of cultivation. The other is abandoned in the reeds, to travel alongside an old swordsman through the mortal realm… As fate advances, how will the two fight destiny? Will they be able to reunite?
From Xia Da, creator of Song of the Long March!