Immortality Begins with Defying the Demoness

Xu Xian transmigrates to a cultivation world and becomes a cultivator with a useless spirit root.

Fortunately, he can spend his lifespan to simulate and refine his cultivation!

Anyone poisoned by him loses a day of their lifespan every second, while his own lifespan keeps growing!

His enemies always think they'll be fine once the poison is cured, but they keep dying for no apparent reason!