Someone that is powerless battles with fear, which -- of course -- creates many fearful things; Someone that is powerless battles with fear, which (of course) creates many fearful things; Someone that is powerless battles with fear, which of course creates many fearful things. The last sentence may be helpful if you want "of course" to be an important part of what you are trying to express; "of course" in the first two sentences is just an extra idea that could easily be deleted.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.