Aerna of Pain, can't damage two creatures

Back at the arena of pain, two creatures appeared that both my swords and magic have no effect on, one is a skeleton and one a cyclops. How do I have any attach effects on them? Stuck here on that! Thanks!

For the skeleton, if it's the one I think it is, you need to destroy the four blue pillars by hitting them with the blade Agony. That's on a shelf in the far southeast. Then you can kill him with any waeapon. Same thing for the Cyclops.

For the skeleton, if it's the one I think it is, you need to destroy the four blue pillars by hitting them with the blade Agony. That's on a shelf in the far southeast. Then you can kill him with any waeapon. Same thing for the Cyclops.

Darn, they followed me to the entrance of the arena, so I won't be able to get to the final pillars I missed before they came after me