Chaotic Evil Alignment

Chaotic Evil people are those that put themselves and their pleasure before others. They completely disregard law and order as well as the welfare and freedoms of others. They are the only people that matter. They will hurt and eliminate others when it is useful or pleasurable for them to do so. They don't respond well to authority and will only obey another person if they believe that they will gain something from doing so or if they are forced to do so. These alliances will always be on a timer though. Once they have gotten what they wanted or feel their is an opportunity to escape the authority they will move on. When moving on they will usually not leave much behind them as they are prone to taking revenge and being spiteful.
This means that they are not going to work well in groups. They are never going to compromise or be willing to wait to have their needs or desires met in order for someone else to have theirs met. Thus, they are loners. When they have others around them it is as a tool that they will keep for as long as they are useful and then they will toss them aside. They will lie, mislead and manipulate others to get what they want. There is no reason to keep a promise because it was only made as a way to manipulate others. Since they are driven by their desire to fulfill their needs and whims, they tend to be impulsive and impatient. They have unfettered emotions that they see no reason to suppress, allowing them to explore even the darkest urges and desires.
Planning is important to maintaining their freedom and themselves. They will do what they must to survive even if that means they must delay their pleasures for a time. But they will scheme and plot to create the escape that they need to devise the social situation that is required. They will work to get what they want. But there is always the undercurrent of uncontrolled emotions that rules them which makes them unpredictable. This means that they could respond very differently to the same situation depending on their mode or the day they have been having. Their stress levels can greatly impact the manner in which they behave. One day they might feel no need to respond when someone insults them, but the next day they might kill them for it.
Law and order does nothing but protect the weak. This does nothing but hold back the strong and dilute the strength of the society. The weak only have value if they are able to serve the strong. There is no empathy or compassion for others. People have the same value as objects. If it is functional and helpful to them, they will keep it but if it isn't or it is broken then they will discard or destroy it. There is no point in keeping broken things.
Since people are objects, they deserve nothing. They will engage in behaviors more extreme than most because of this objectification of others. They will cause harm to innocents, kill when it isn't entirely required, poison people, use violence to gain power and they might engage in these kinds of behaviors for the pleasure of dominating others or on whim or in a rage.

Chaotic Evil. (CE) creatures act with arbitrary violence, spurred by their greed, hatred, or bloodlust. Demons and red dragons are typically chaotic evil. -5e Basic Rules, Chapter 4: Personality and Background