Swinging My Sword at the Future Demon Queen

As the college entrance exams approached, Duan Huaige unexpectedly discovered he had a system from the future: [In the late stages of the Spirit Energy Recovery Era, the ruthless and mu*derous Demon Queen Jiang Xiyu committed countless atrocities. Her Human Emperor Banner claimed the lives of countless cultivators, and she became the scourge of the righteous path! Faced with such a monstrous villain, every righteous cultivator is obligated to exterminate her! Although your cultivation is not yet strong, you must still have the courage to draw your sword against the powerful. Declare war on Jiang Xiyu to defend the last shred of justice in the world! Reward: Introduction to the Dao of Mountains and Rivers.] Duan Huaige: ? The Demon Queen you’re talking about… is she the same Xiao Jiang, my high school classmate who fights me to the death over grilled sausages and stuffs herself with takoyaki until she looks like a chipmunk? No need to explain further—defending the glory of righteousness is our unshakable duty! While shamelessly taking advantage of the future big villain, Duan Huaige comforted himself with this reasoning. However, he gradually realized that the missions were becoming more and more absurd. [After a life-and-death battle, both the villainous Demon Queen childhood friend and the pure and chaste Sword Immortal of the righteous path are gravely injured. However, you only have one vial of spiritual elixir capable of saving them.] [As a modern man who has studied pharmacology and biology, you understand that oral consumption is not the fastest way to absorb the potion. In order to achieve the best of both worlds, you will use the most scientific method to achieve a dual-save ending!] Duan Huaige: ? The absorption method you’re talking about… surely you don’t mean…