Da Tang Shuang Long Zhuan

This story is set during the end of the Sui Dynasty, a time where multiple powers struggled for supremacy and power. Into the fray enters two orphans Kou Zhong and Xu Ziling; these two youths by many chances and luck obtain ‘The Secret to Long Life’ allowing the two to obtain profound martial abilities and a chance to rise to the top in this age of turmoil. — Description from novelcodex.org