|Braino of Mrynah|
- Real name: Braino
- Identity: Public
- Alignment: Good
- Gender: Male
- Occupation: Hero
- First appearance: Adventure Comics #320 (May 1964)
- Appearance of death: Sometime prior to Adventure Comics #320 (May 1964)
- Universe: Pre-Zero Hour
- Alternate versions: None
Braino of Mrynah: All we know is what his tomb tells us, that he was the "noblest being of all time", who used his great mental power to funnel all the evil of his world into himself, and died of it.
After the five-year gap, Matter-Eater Lad had Polar Boy don a costume of Braino (basically just a giant fake head), in an attempt to plead insanity during a court case. Though this attempt failed, it actually did play a role in getting the charges against him dismissed.