system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] What exactly is Brainiac and what are his powers? What makes him such a big threat?

Is he on par a threat as Darkseid for example?
gpt
Brainiac's origin has changed quite a few times over the years.  He was originally a single member of the Coluan alien race, then an alien supercomputer, then a Kryptonian supercomputer in the Superman animated series.  Regardless, his modern incarnation is obsessed with his own improvement and the study, categorization, and destruction of all other species.  He's very Borg-like in that respect.  His powers are technological, intentionally nebulous, and often chosen by writers to facilitate the theme and storyline of the comics, which usually center on dehumanizing mechanization.

As a threat Brainiac is considered extinction-level.  Unopposed, he will wipe out all life on Earth.  He's been a threat to a weakened Darkseid in the past, but their goals rarely intersect.