Random Smartest Characters in Comic Books (20 items)

(#2) Mister Fantastic

Reed Richards, despite his physical powers, considers his mind his most invaluable asset. In fact, he's been known to use his stretching powers to increase the size of his brain in times of need. In the comics Richards is an accomplished theoretician, and is noted for his breakthroughs in the fields of space, time, and extra-dimensional travel, biochemistry, robotics, computer science, munitions, and more.

In fact, the Fantastic Four is largely financed by his own valuable patents.
(#15) High Evolutionary
Otherwise known as Herbert Wyndham, High Evolutionary started out as a student at Oxford in the 1930s. And we all know Oxford is so easy to get into. So there's that right off the bat. He later began experimenting with genetic manipulation and became obsessed with the idea of using his inventions to evolve a better world at any cost.
(#8) Professor X

Professor Charles Xavier is the founder and leader of the X-Men, a world renowned geneticist, and the inventor of Cerebro, a device he uses to telepathically scan the world for mutants. Largely considered the one of the most powerful telepaths in the Marvel Universe, he is able to perceive the thoughts of others or project his own thoughts to great distances -- in one case across the entire planet.

He's the definition of the type of guy you really don't want to challenge to a game of "Pick a Number Between One and a Billion."
(#7) Beast
He's a giant blue, hulking, hairy, red-eyed... well... beast. But Hank McCoy is also one of the most intelligent beings in the Marvel Universe. He's the X-Men's dedicated doctor, and an instructor at the Xavier Institute who also found the cure for the Legacy Virus in multiple X-Men story lines.
(#4) Lex Luthor
- Superman: War of the Worlds, Superman: Birthright
Lex Luthor is Superman's greatest adversary and considered the most intelligent human in the DC Universe. With his genius level of intelligence, he has mastered nearly every known form of science, including space and extra dimensional travel, biochemistry, computer science, robotics, munitions, transportation, holography, energy generation, spectral analysis, and more.
(#6) Batman
- Superman/Batman, Identity Crisis, Batman Confidential, Detective Comics, Batman, Batman: Legends of the Dark Knight, Batman, Batman: The Dark Knight Returns
In the DC Universe, Batman is considered the world's greatest detective, and able to solve practically any crime. While Bruce Wayne has no actual super powers, he boasts a genius intellect and is a noted polymath. It also doesn't hurt that Wayne's near inexhaustible wealth grants him access to scores of advanced technology, and as a scientist, he is able to freely modify this tech to his advantage.