I Have No Health is a Manga/Manhwa/Manhua in english language, Manhwa series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

I’ve gone into the body of ‘Ninaina’, the weakest character, who was fated to die once winter came! With such with weak stamina that it’s hard to even take walks, eat, or just stand, let alone exercise, I have such a tragic life that I even have to endure assassination attempts from my grandfather… “I will definitely recover my health!” “Kaiser” who comes to Ninaina’s side with a cold gaze. Receiving the order that he has to keep Ninaina alive, he comes to her side and protects her. “You will not die. For now.”