Normal Fire Runes need a Sunstone along with a Blank Rune; a Silver Ingot and three Weak Fire Runes to make one Normal Fire Rune.
Normal Runes can be crafted at level ten at the Rune Altar.
You need three of these to learn Fire Slash and you will need extra to cast the spell.
The command to make a Normal Fire Rune is [nya!rpg rune altar fire]. For more info use [nya!info normal fire rune].