I would like to note that you misunderstood “lethophobia”. Oblivion does not mean the end of the world. Oblivion means forgetfulness, related to oblivious. The leth- root refers to the river Lethe, one of the rivers of Hades and the river of forgetfulness. Lethophobia, therefore, is not the fear of the end of the world, but the fear of forgetting.