Byoujaku Mama desu ga, Yami Ochi Musuko o Sodatete Misemasu!

After dying and waking up again, she finds herself in the world of a trashy romance fantasy novel she had read while alive. Worse still, she has reincarnated as the villainous stepmother who is destined to be killed by her darkened son. No way. She refuses to die like that! She is determined to stop her son from falling into darkness at all costs. …But despite her resolve, this body turns out to be extremely frail. She collapses after walking only a little, can barely do anything properly, and if she pushes herself too hard, she might die before her son ever gets the chance to kill her… She must become healthy, shower her son with love, and destroy every last death flag! Thus begins the desperate survival strategy of a sickly mother doing everything she can to stay alive. Original Webtoon: Comico, LINE