“ A race that are always born as twins and only one recieves a soul. The other is soulless therefore without pity, shame, or guilt. The evil race. Can't tell them apart by looking at them.”
“ Have a large room that elevates either up or down when triggering a trap. The floor can bring the players to new levels, where a mighty beast roams, or the floor flattens the players into the ceiling or drop into a pit of lava.”
“ If you want to add a 'supernatural' touch to your campaign, define the rules of magic and the universe. Make your players comfortable with those rules. Then your new supernatural creatures must then break those rules.”