It follows that if there is good there is evil. And if there are entities that fight for good, there are entities that fight for evil. What many humans discount is the power of evil that is present in our lives because many only want to interact with the good in hopes they will intercede for them. If the good entity does intercede against whom is the good entity striving?
There is evil in our world and there are entities – demons, arch-demons, shades, shadows, ghosts, et. al. and many are ancient and very powerful. They prey on human weakness, be it arrogance, greed, lust, sloth, envy, gluttony, or anger. All serve dark masters and all pass power to evil. Fear is one of the greatest tools evil entities have over you and once you realize fear is a tool, it becomes harder for evil entities to use it.
Creating a level of abstraction is one way to face fear. What this means is to look at the situation from an observers viewpoint. How does this look or feel to an outsider and what is the final outcome? This is not really affecting you but it is happening to someone else and if so that gives you power over the situation.
Was there ever a time without evil? Not since life was sentient. There has always been a juxtaposition of good and evil and there always will be. We must live with a full understanding that there are forces outside of us that wish to affect us negatively.
So things that have gone poorly for you be it health, professional, personal, spiritual, financial, or sexual can all be potentially traced to evil entities. While this is many times the case and why must it be this way?
Entities, both good and evil, gather life-force from living beings as a way of continuing to remain viable.
What this means to all sentient beings is that guarding our thoughts and actions can truly drive the energy we wish to reinforce. Create positive energy and it drives positive things, and create negative energy and it drives negative things.