But there are many other characters who do this as well. For the fall to work well, it has to start with a character who we love. We might ever like them because of their flaw, something they have that challenges the status quo. They are a character who doesn't like doing things as they have always been done, and often find themselves taking shortcuts to accomplish what is required without having to take the time to do it the required way.
Typically, the precursor to the fall is this character challenging ideas and routines with more passion than they did previously. They often are chastised, which tends to fuel the rebellion within them. The fall ends one of two ways. The first, and most common, is with some kind of tragedy, two of the most common including being locked away forever or dying. These include Cruella Deville, Magneto (sometimes), Ursula, Voldemort, and probably many others you can think of.
But not everyone who experiences a fall is lost. The other possible outcome is redemption. This is often brought about by a stark realization by the character of what they have done, but also is brought because someone gives them a chance when they thought it was no longer possible.
Some characters who experience redemption are Darth Vader, Snape, Loki (sometimes), Miss Hannigan, Inspector Javert (though his redemption does cause a realization that brings about a price. We could argue this one for a while...) and others.