Meiou-sama ga Tooru no desu yo! @comic

Osamu is a young man who died at a young age due to an incurable illness. His second life was to drift as a spirit (demon) in an unknown world! Osamu, who is hated by humans and unreasonably deprived of his "life," does not want to die anymore. At that time, he gained the power of "life-sucking" that feeds on the vitality of others. In addition, he will resist the approaching death by using the science that he learned in his previous life and the creation magic that makes the best use of his own dexterity. One day, he met an immortal girl was also in despair. "—You tried to kill me. You guys are bad." In order to live, the pair leans into the evil side. An anti-heroic fantasy where a ghost who wants to live and a girl who can't die conflict with the world! (Source: TO Books, translated)