Fantasy, After Time Travel, I Am a Demon Cultivator!

[Invincible background, decisive killing, not brainless, single female protagonist or no female protagonist] I am willing to fall into the endless abyss and prove the Tao through demons! So what if the sky is stained with blood and millions of corpses are buried? The world is not kind to me, so I, Wen Xuan, will destroy this false world! ... What? I just traveled through time and was reborn and you asked me to be a demon cultivator? Killing someone as a villain? I, Wen Xuan, can't even step down to kill an ant, and I have to go over and help an old lady crossing the road. You ask me to do this kind of thing? ... "My name is Wenxuan, and I am a good man!"