Painted over the sigils in the basement -- should I be worried? (Quelmire)

So I spent last weekend painting the basement. Primer + two coats, really cleaned the place up. My wife pointed out today that there were some markings on the east wall that are now covered. I assumed they were from a previous owner's kids -- looked like someone drew them in marker? Sort of circular patterns with lines through them, maybe 4-5 of them spread across the wall. Some were behind the water heater so I had to really get in there to cover them.

Is this a thing I should not have done?