Sly

Where to find
Sly can be found in the Forgotten Crossroads, after defeating the Gruz Mother.

Sells

 * Mask Shard: 150 Geo
 * Mask Shard: 550 Geo
 * Vessel Fragment: 550 Geo
 * Vessel Fragment: 900 Geo
 * Simple Key: 950 Geo
 * Gathering Swarm: 200 Geo?
 * Stalwart Shell: 200 Geo
 * Lumafly Lantern: 1800 Geo
 * Rancid Egg: 60 Geo

Trivia

 * According to a livestream Q&A, the development team originally planned for Sly to be a difficult boss who wielded a nail approximately the size of the other Nailmasters'.