Brainiac 5

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

Brainiac 5 is a member of the Legion of Super Heroes in 30th Century Metropolis. Possessed of a 12th level intellligence his many inventions have included the Legionaire's time bubble, Mon-El's cure for 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.