Literal translation is the face changes colour. Meaning wise is to say some one has some drastic mood change e.g. Like someone goes red in the face from anger or purple from envy etc
... possible meaning - 面部 - face (the body part) 改 - to change/ to alter/ to alter/ to transform/ to correct 色 - color/ look/ appearance (could also be sex/lust) In the context... 如果是绝世枭雄一级的人物，- in the event that a man becomes a powerful character, 绝对会面部改色，he can absolutely change the appearance of his face. --> this is literally changing the look of the face ...like a disguise... my understanding in your context is that, only upon reaching a heroic-level kind of power, can the male protagonist disguise his appearance .... 让她们去死。- let them go to hell. 自己想做什么就做什么，- do what you want to do 丝毫不受影响。- not be affected in the slightest. ...hi, i am in the process of learning Chinese... so, if you get to know the correct meaning, please let me know as well, as i might encounter the same in the future.. thanks! ... tried to translate your context as well.. for additional exercise...
In the given context, I reckon there's a typo error, what will be more fitting in this case should be 面不改色. Basically it means without hesitation/ faltering, he/she would just watch them die.
You are absolutely right, Retrospect. Of course this is a typo error, for 面不改色 is just a commonly used Chinese idiom. And we also often say another longer idiom - 面不改色心不跳. literally, we can translate it like - without their face ever changing color. Basically it means - Remaining calm even facing a bad situation. While searching corresponding English idioms from youdao online dictionary (有道翻译)，finally，I found two - not turn a hair and not bat an eye/eyelid(UK). And I also want to know whether it's proper to use "with a poker/emotionless face"? glad to see you are studying Chinese, wish you a happy journey.
Five minutes ago, one of my friends with American education experiences told me another version - calm like shit. I don't know whether it was just a joke or an American can accept it?
In this situation of watching someone die, I feel that "emotionless face" would fit better than "poker face." When I use "poker face," it is typically in situations where the person being described should have a particular emotion on their face; for example, telling a joke or a funny story with a poker/straight face, winning the lottery or getting bankrupt with a poker face, or always having a poker face and never smiling all though school. But in this case, I feel like he just doesn't care about the person dying at all, or thinks so badly of them that their death is nothing to him. Crude but apt.
i was thinking about: they would let them die 'with a straight face', which complies with your understanding. Thanks a lot