Brainiac 4

Brainiac 4 is the name of two fictional characters appearing in American comic books published by DC Comics.

Pre-Zero Hour/Post-Infinite Crisis
The Silver Age version of Brainiac 4 is Kajz Dox, the father of Querl Dox (Brainiac 5), who died when Querl was a child.

Post-Zero Hour
The second Brainiac 4 first appears in Legion of Super-Heroes #107 (August 1998). This incarnation is Brainiac 5's mother and the leader of the Dark Circle who joined them in an attempt to alleviate her longtime inability to feel emotion. After being defeated by the Legion, she is committed to an asylum.

In Mark Waid's Legion of Super-Heroes reboot, Brainiac 4 appears as one of several Coluans who were infected with a mind-altering illness during an attack on the United Planets.

In other media
Brainiac 4 appears in Legion of Super-Heroes (2023), voiced by Robbie Daymond. This version is a clone of Brainiac and member of the Dark Circle who was created to steal the Miracle Machine. After his failure to do so, Brainiac fuses him into himself, but Brainiac 5 later manipulates Brainiac 4 and his fellow clones into fighting and killing one another from the inside.