Spiritual attacks
What are spiritual attacks? This question is brought up on this board, but it rarely leads to any good answers. I will here explain my understanding based on Falun Dafa, the theory behind the Falun Gong movement, which during the effective years was almost entirely focused on defence against spiritual attacks.
In Zhuan Falun is explained that a person has karma, which is a black energy mass. A person also has virtue, which is a white energy mass. Virtue and Karma are the terms De 德 and Ye 業, same "De" as in as in Dao De Ying 道德經.
The word Ye appears in the Chinese word for homework 作業 (zuòyè).
During your life, or during a previous life, you created karma by doing things which harm other people, animals or plants. Anything which is alive counts, so even living a normal life or being a vegan, you still harm plants by eating them. This creates karma, and it appears as a field around your body.
This black field will serve as an environment where negative spirits can reside, so they get in there and just sit there. From that position they can manipulate your body which is connected to the black energy mass, and this causes illness. Then can also penetrate your brain and manipulate your thinking. This is spirit possession, in common terminology. Exorcism removes the evil spirit, but it doesn't remove the black mass of energy, so a while later, a new evil spirit will get in and you'll be ill or possessed again.
The karma which appears will have different nature depending on who was harmed. If killing small animals, you'd consequently face evil spirits associated with small animals. If harming another human, it will be more complex. Because everyone had karma, evil spirits will see the link between two people, and use it to influence them. So when there is a black string of karma from one person having harmed another, these spirits will make the person hate the one who wronged them, and causing them to retaliate. The person who was now retaliated against, will not see that this was caused by evil spirits and the karmic bond, but will retaliate against the retaliation, which creates karma for the other person instead. The perpetrator is now the victim. This causes cycles of conflict which may escalate into war between groups and even nations. If no one realizes that they need to stop, it will spiral into the destruction of empires and keep happening until all infrastructure has been destroyed. After this happens, people cannot retaliate anymore, and the evil spirits become unable to create more conflicts.