Brainiac 5

Originally thought to be the descendant of the original Brainiac, Brainiac 5 is actually descended from Brainiac II (Vril Dox), who was adopted by Brainiac I to hide his origin.

Brainiac 5 (real name: Querl Dox) is a member of the Legion of Super Heroes in 30th Century Metropolis (Act No. 276/2, May 1961: "The Three Super Girl-Friends"; and others.) Possessed of a 12th level intelligence commmon to his homeworld of Colu his many inventions have included the Legionnaires' time bubble, the cure for Mon-El's lead poisoning, flying belts, flight rings and Computo.

Both Supergirl and Brainiac 5 applied for Legion membership at the same thing but Supergirl was rejected as Red Kryptonite had turned her into a Superwoman and over the 21 age limit for membership.

As depicted in The Chronicles repeatedly, Brainiac 5 and Supergirl are sweet on each other.

When Superman visited the 30th century to answer a summons from the Adult Legion of Super Heroes, he was greeted by their leader - Brainiac 5.