"Blue leg" hermits is generally the common name for Clibanarius tricolor, which has bright orange eye stalks/antennae, blue and orange banding on its legs, and black pincers with white spots...pretty crabs, actually.
As for your crab, I looked around a bit, but had little luck finding "your" critter, altho I believe I found a photo of the same species on a Korean reefer site, but its legs were quite a bit more blue, which could be specimen variation.
Bottom line, is I'd keep an eye on it, and maybe relegate it to "sump monkey" status until you get a better handle on the ID or see how it behaves.