H.I.V.E.mind was quite a "new" addition to H.I.V.E. when book one began, having been brought online four months, three weeks, two days, four hours, thirty-seven minutes and three seconds ago when Laura asked. He proved to be an incredibly useful addition to H.I.V.E., running all the day-to-day things that happened in H.I.V.E. Laura Brand was fascinated with him when she first met him, aware that H.I.V.E.mind was cutting edge.
Otto also took great interest in the A.I. and found out that though he was not allowed to exhibit emotional response he could still "feel" and was unhappy at H.I.V.E.
Later on in the book Otto and Laura are about to shut down H.I.V.E.mind with an EMP as part of their escape attempt, he appears and tells them not to, saying that it will "kill him". He then asks the four teens to take him with them as they escape from the island, which they do. They do this as he transfers himself to a small tablet which he can transfer himself and his functions to.
When Nero and Raven foil the escape attempt Nero has H.I.V.E.mind shut down, to Laura's dismay as she has grown to like the A.I.
In book two H.I.V.E.mind is booted back up after being shut down, but he is not the same. Professor Pike, under Nero's orders, has placed restraints on H.I.V.E.mind, so he can't feel emotions as he did before. Laura is upset by this, believing it is her fault. After H.I.V.E takes over Cypher's giant assassin robot and attacks Cypher with it, Professor Pike lets Otto delete H.I.V.E.mind's behavorial restraints.
H.I.V.E.mind has a wire-framed blue face and is often referred to as "Big Blue" by the students. He is an artificial intelligence, and is Overlord's brother. His coding is so similar to Overlord's that in Rogue, Cypher mistakes his code for Overlord code.