Zirong sat cross-legged under Doctor Sun's guidance, starting to gently circulate Qi using the method taught by him. To heal Yu Qingwan, his Qi wasn't necessary, but to awaken the power of life origin for Yu Qingwan's use, Qi was indispensable. Fortunately, he had reached the Realm of Great Swordsmen; otherwise, anyone weaker wouldn't even have the right to stake their life on such a risky endeavor.
"Young Master Zi, you must think carefully. The Meridian Replacement technique can only be used once. In saving Miss Yu, the venom will remain in your body forever. There's no cure, and your lifespan will depend on how long Young Master Ye's seal holds. Once that seal is affected by the venom, even a Heavenly God descending couldn't save you." Doctor Sun reminded everyone once more when they were all prepared.
