Treating Illness with Illness: Quick Transmigration

One day, a mysterious person suddenly appeared in the home of a doctor who had always loved peace. Mysterious Person: Autumn is here. Please become the savior! Doctor: Not interested. Mysterious Person: But the future Demon King is at stake. Please, sir! Doctor: Then just kill him. Mysterious Person: ...We don't have the ability. Doctor: Then what do you want me to do? Mysterious Person: Fight poison with poison, treat illness with illness. Doctor: ??? [First World] The doctor is "talked into" joining a certain System. Before the mission begins, he casually chooses the severe condition of [paralysis]. He only wants to experience what the tyrant patient will go through in the future, for his research. Who could have guessed... The first thing he sees when he wakes up in the hospital is the future Demon King's caring gaze. Doctor: So this is what they call being irritable...? Reading Guide: 1. The protagonist is a perfect male lead with no romantic pairing. Love is fatherly love, like an avalanche down a mountainside, and affection is socialist brotherhood. 2. The protagonist has no romance plot and comes with the aura of an immune-to-love single noble. Some supporting characters have pairings. 3. The author is chatty. If you don't like that, feel free to hide the author's notes. No worries~ *World List* World One: [The Bro-Con's Victory] Modern wealthy family, paralysis World Two: [Strange Folk of Yanzhou] Ancient power struggle for the throne, alcoholism World Three: [Six Calamities] Fantasy, Demon Venerable of the Six Realms, narcolepsy World Four: [Gossip in the Divine Realm] Fantasy, divine realm, blindness World Five: [The Medical Immortal] Ancient, the two peaceful states, consumption World Six: [Twins] Modern murder mystery, depression World Seven: [Infinite Terror] Full-dive online game, poor gaming skills World Eight: [Judgment] Western fantasy, divine followers, heterochromia World Nine: [Black-and-White World] Modern artist, color blindness World Ten: [Guarding the Pass] Ancient Chinese-style wuxia, deafness Bonus Worlds: [The Scholar's Virtues] Modern top student, forgetfulness [The Dawn of the Apocalypse] Modern apocalypse, hemophobia Extra Volume: Past and Future [For more information, see the volume labels and summaries.] *Feel free to follow the author's page and check out their other stories. Theme: A so-called Demon King is just a patient waiting to be treated with kindness.