Kryptonians are an alien humanoid race of being who originate on the planet Krypton. Kryptonians are basically humans in their structure and appearance. But their biology is far more advanced than that of Earth based humans where they are able to utilize energy in their body with far more direct and elaborate manners than Earth based humans do.
Various dimensional Kryptonians have developed superpowers in regards to Earth based humans that vary drastically in comparison to their various native dimensions. Super speed, heat vision, x-ray vision, and super breath are among many Kryptonian superpowers.