Nimes Josaih McCainne is introduced in the story within the second and a prominent figure within the third arc of Locksmith: Boundaries. An enigmatic sophomore who starts within the second term of the school year in Alastair's class, the enigmatic sporty kid has a lot more than meets the eye. A Key attached to the Earthly Hollows key ring, Nimes, along with his two brothers and their Keeper and adoptive sister, are tasked with goal of recruiting Alastair into a secret society of Keepers and Keys who have renounced their loyalties to the Locksmith and wish to usurp his power and kill him.

He's one of the first keys introduced within the story that is another key aside from Alastair and their key ring, so their powers follow a different schematic than Alastair's, as Alastair's keys all have Wind Affinities. As well as, since Nimes original contract wasn't through a Surveyor, and was from a Lockpick, his powers differ once his contract is renounced. Upon meeting and their first few skirmishes, Nimes powers are earth based, with geokinesis and the ability to reinforce the solid matter around them to the strongest degree imaginable, making his defenses impregnable to a considerable degree. Along with being able to expand the matter around them as well, he also has the ability of clairaudience, and uses it to his advantage to track down Alastair, despite his terrible sense of direction.

Quick to think on his toes, and rather academically smart, they're a sly character that loves to crack a joke to lighten the mood. Of course, he has a tendency to get attached to people rather quickly, which gets in the way of his work. He ends up dating Alastair, nearly forgetting his original goal in mind, which helps the fourth arc go in full swing.