Ridill

Ridill (リディル) is an extremely lethal Demon Sword that goes by the names Baleful Venom Blade and Dragon Blood Born Dragon Slayer in "Highschool DxD: Of Kings and Pawns."

Summary
This vile, single-edged sword was previously wielded by Regin; he was the dwarf brother of Fafnir and foster father of Siegfried who aided the original Siegfried in killing Fafnir only to be killed by Siegfried after his discovery of Regin's plans to kill him. This sword was used to carve out the heart of Fafnir; which wound up binding a venomous curse to the blade upon completion as a result of the malice and greed within Regin's devious plot manifesting and merging with Fafnir's own blood. This sword reeks of malice and murderous intent; so much so that the Norse gods don't dare to even hold it for prolonged amounts of time.

As of now, this blade is held within Valhalla as the Norse gods fear the possibility of a twisted and evil person wielding such a deadly weapon.