Achidna was a beast feared throughout the realms, even Death had heard of her. She once ruled the shadow realm Ysilik "where the sisters sightless spin their webs." She once had an encounter with Thane and because of this "old debt" the Maker sought to kill her.
He tracked her to her home only to discover her throne bathed in blood, the spider lords already fighting over succession. Thane relentlessly hunted her throughout the Dead Plains but the Forge Lands came under attack by Corruption and he had to leave the debt unpaid.
While in the Psychameron on his quest to retreive Basileus for the Dead King Death discovered that Achidna had become the pet of Basileus. Death killed her to subdue Basileus and as a reward received Achidna's Fangs.