Blur is one of the Gnomes who works at Everglade, the goblin-run resort and spa. They're basically the resident expert on, well, blurring things.
I love this little detail Shannon Messenger adds — it's such a fun, functional bit of world-building. In the world of the Lost Cities, Gnomes have various specific talents tied to nature and craft, and Blur's whole thing is using minerals and crystals to create visual distortion fields. Their main job, as I recall, is maintaining the privacy shields and the 'blur' around the resort's more exclusive areas, like the healing pools, so that the elven patrons can relax without being seen. It's not a huge plot role, but it makes the world feel lived-in.
It's a neat, subtle way to show the cooperative (if sometimes tense) ecosystem between the different intelligent species — Goblins running the business, Gnomes like Blur providing the magical upkeep, and Elves being the wealthy clientele.