Who or what will be tormenting those people cast into the lake of fire since Satan and his kind will be cast into the lake of fire as well?
In Biblical times The Dead Sea came to be known as a model of the Lake of Fire judgment. Being a model, it doesn’t tell the whole story, but it will give us some idea. Picture this.
The mineral content of its water made it impossible for a person to sink in the Dead Sea. Whenever someone tried they would just bob to the surface again. Back then a tar-like substance called bitumen used to seep up through cracks in the sea bed. Being lighter than water, it floated to the surface where the Sun dried it. There was so much of it people used to go out in boats and harvest it. Sometimes a lightning strike would set it on fire and the whole surface of the sea would burst into flame. It was a lake of fire.
Now imagine being in the middle of the Dead Sea when it’s on fire. You can’t dive below the surface to escape the flames, but you can’t stay on the surface because it’s burning. No one has to hold you there but you’re trapped just the same. If you stay on the surface you burn in the flames, but when you try to escape by diving below them the water pushes you back up. Now suppose you’re unable to die and have to spend eternity trying to escape the flames. Get the idea?