Zodiakol, or the Bloodmetal, is the "mage-slaying" elvish red metal that the Red Arrows are forged from. The method of its creation is a closely guarded ancestral secret of the elves. It is believed that if any non-elf were were known to be carrying any bloodmetal, the elves would hunt them down and kill them to take back the metal.
Properties
Like all of the ancestral elvish metals, zodiakol takes enchantment very well. It also inherently possesses a anti-magic property; arrows forged from zodiakol are able to dispel or pierce any protective wards that a target of theirs has active.
Behind the Scene
Initially, it was said by Lady Sariel that
“I have given you arrows of liannar, the bloodmetal. Made by father. Forged in the same fire and of the same steel as the Teeth of the Dragon. Use them.”
Leading to the belief that that liannar and zodiakol were the same metal. Matt later clarified that he had always intended for the arrows to be forged from different metal.