Neverseen Cloaks are special black cloaks worn by members of the Neverseen. They are black, baggy, and have a hood which casts a complete shadow on the wearer's face. The sleeves of the cloaks also bear the trademark white eye symbol.
The main purpose of the cloaks is to mask the wearer's identity. Because of the fact that the wearer's face cannot be seen, Polyglots can use these to imitate and mimic voices. This was used in Neverseen by Keefe and Sophie to try and trick Gethen into giving away vital information. It was also used earlier in the series in Everblaze by Lady Gisela in the battle on Mount Everest to make Keefe think that he was speaking to his father, Lord Cassius.
The cloaks are noted as having a lining that small objects can be hidden inside of. In Lodestar, a tracker was placed in the cloak that Keefe was given by the Neverseen, and in Unlocked Rayni reveled that she had hidden a starstone that led to the Neverseen's Storehouse in her cloak's lining. The fabric that the cloaks are constructed from is thick and can protect the wearer from glass shards, such as in Lodestar, where Sophie was protected by a Neverseen cloak from an explosion that caused the glass walls of the Foxfire pyramid to shatter.