In the Harry Potter series, the three major unforgivable curses are: Ada Ked, Imperio, and Crucio. Not only do these spells have great magical powers, but they are also considered immoral and inhumane, so they are listed as unforgivable spells.
The Killing Curse (**ada ked**ra) is a very dangerous spell that kills the target directly. This spell is extremely taboo in the wizarding world because it violates the principle of protecting human life. The use of the Killing Curse will not only result in the death of innocent people, but it will also upset the balance and stability of the wizarding world.
An imperio is a spell that controls the minds of others. Use this spell to impose your will on the target person, making them your own puppets. Such control not only deprives the target of their personal freedom, but also makes them lose their dignity and self-esteem.
The crucio is a very painful form of torture that inflicts unbearable pain and torment on the target. The use of this spell can cause a person to suffer a double blow, both physically and mentally, and may even lead to death. This pain and suffering is inhumane and is therefore classified as an unforgivable mantra.
In addition to these three unforgivable spells, there are other taboo spells, such as expecto patronum, muggle-repelling charm, and nonverbal spells. Each of these spells has its own unique role and use, but they also need to be used with caution to avoid undesirable consequences.