How weak is this intro of my essay?

Your thesis statement should state what you are going to talk about in your essay, often it is best to write it after you have completed the essay so that you can pull important points out and highlight them. From what you have written it is not clear what you are going to talk about, are you talking about what others call him, defend his actions based on what happened in his childhood, or are you just going to talk about his childhood? Without knowing your whole essay it is hard to write the thesis statement, which is why I suggest you write it last and pull your key arguments out.