There's a character who aims to improve their situation in life, be it in terms of money, fame, or power. There is a high probability of this character starting out as evil or becoming evil very quickly. The Visionary Villain and Well-Intentioned Extremist will do horrible things to achieve their Heaven on Earth; The Social Darwinist and The Sociopath will commit every act of crime and manipulation to move up the ranks; the Corrupt Corporate Executive began as a dirt-poor proletarian who wanted to live wealthy, etc. Upon attaining this power, they'll likely forget whatever it was they wanted it for in the first place. The Illusion of Pride, and the inevitable tale of Tragedy for the one who dared to be ambitious is likely.
Fictional and Real Life moral codes have a tendency to demonstrate Selfishness, Greed, Pride, Megalomania, and Machiavellian Chronic Backstabbing Disorder as a consequence of the catch-all term "ambition". If you consult a dictionary it's broader than that. Ambition is the same thing that motivates some heroes to make the world a better place, but in that case, it's more likely to be called "Hope".
This trope is one of the reasons why Villains Act, Heroes React. Villains who don't have great ambitions would not plot grand schemes and motivate story driving conflicts such as Take Over the World or Utopia Justifies the Means, and, therefore, would be boring and petty. It is possible to write an "ambitionless" villain — see For the Evulz — but they risk coming off as a Generic Doomsday Villain.
Usually justified when the existing society is an evil dystopia, or otherwise flawed — "advancing" in such a society would generally mean complying with or encouraging its systemic injustices.note Also justified when ambition, or other emotions, is the personification of evil itself.
Can happen as a result of Status Quo Is God. Normally used as an heavy-handed Aesop about what's really important. Unfortunately ends up in a Broken Aesop that teaches us Evil Is Cool (or at least open to social progress).
The Svengali, since their goal is usually to profit through their (supposed) protege, will usually be an example of this, and turn their protege into one, unless they realize in time.
This is a common trait of The Starscream; indeed, it's often what makes them The Starscream.
The heroic converse of this trope is To Be a Master, where the hero is motivated by ambition. Note that heroes tend to pursue "healthy" goals such as strength and knowledge, while villains are more likely to be after power or money, usually for their own benefit and no one else's and at other people's expense.
For some reason, while even high levels of ambition are bad, equal or greater levels of determination are usually presented as good, or at least not bad. If you have high levels of both, you're The Unfettered. Heaven help the character intending to use their super powers this way; it guarantees Screw the Rules, I Have Supernatural Powers!. If a character wants to rise above the level of their fellows, it might be a case of The Complainer Is Always Wrong.
This, in a way, is the inverse of Living is More Than Surviving, where achieving more than the most basic things people can do is seen as good.
See also Pride, Personal Gain Hurts and Evil Virtues. Compare with Drunk with Power. Contrast with Self-Made Man and Go-Getter Girl, who pursue their ambitions, and aren’t (necessarily) evil, as well any Rags to Riches story where The Protagonist means to become rich.
