These are a pair of snakeskin boots, given to you by Mongoose on Mercy Island. You received them after you helped him cull the snake population in a tale you like to call:
It all started when you met Mongoose on Mercy Island. Mongoose was a professional snake hunter working for Arachnos, hired to help keep the Snakes population down. He got you to help him cull the snakes on Mercy, giving you a chance to prove your worthiness to Lord Recluse.
Mongoose then sent you to clear out a nest of snakes infesting the sewers underneath Mercy Island. In the Snake lair you found a strange statue on their leader, a roughly carved idol in the form of a snake. Returning to Mongoose, he mentioned finding similar statues in other Snake nests. Supposedly, the Snakes worshipped some sort of "snake godess".
Mongoose received news about the Snakes from a particular pit where staging strikes on specific Arachnos targets. Mongoose believed there was some sort of Snake leader behind these attacks, and sent you to take him down. You entered the snake pit and discovered in its depths a large Snake temple to their godess Stheno. You took down their high priest S'Thaco and returned to Mongoose for your reward.