Mr. Fantastic

Reed Richards, also known as Mr. Fantastic, is the leader of the Fantastic Four an one of the most brilliant scientific minds.

The Avengers: Earth's Mightiest Heroes
Reed first appears helping Henry Pym analyze Princess Ravonna, seeking a way to save her.

When the Avengers Iron Man and Wasp come to visit at the Baxter Building, Doctor Doom kidnaps Sue and Wasp. The Avengers and Fantastic Four go to Latveria to rescue them, and after a fight Doom just lets them go. What Reed and the others don't know is that Doom has discovered Sue isn't the real one, but a Skrull imposter.

Reed and the rest of the Fantastic Four almost fell victims of the Skrull Sue imposter, but the real Sue somehow saves them.

Some time later, he was part of the Avengers' expanded team against Galactus.