Various Rune Locations:
Light Rune- Go to Chapter 3 and a witch and her sister will give you the rune and a spell.
Fire Rune- Go to Chapter 4 and defeat the Beguiler and his clown to get the rune.
Water Rune- Go to Chapter 8 and reunite the lost brothers to get the rune.
Dark Rune- Go to Chapter 10 and reunite the two children with their mother to get the rune.
Health Tip:
When close to a mushroom ring, save your game , quit and reload to restore health