Johann Schmidt, also known as the Red Skull, is the founder and commanding officer of the modern incarnation of HYDRA, during its time as the science division of the Nazi Armed Forces. A brilliant scientist in his own right, his ambition to become the superior man and conquer the world led him to test the Super Soldier Serum on himself and turn his back to the leaders of the Third Reich.
After his final battle with Captain America, Schmidt inadvertently touched the Tesseract, the very Infinity Stone he planned to use to bring his master, the Dark Inhuman, back from Maveth, and was overwhelmed by its dimensional energies, transported to the cold surface of Jotunheim, where he willingly allowed him to be frozen by the cold weather to survive the harsh planet. Almost 70 years later, Loki attempted to destroy the Frost Giants, accidentally freeing the Red Skull from his icy prison in the process. He was later picked up by a pack of Chitauri who were investigating the now accessible Tesseract energy surge, and taken to Thanos, where he told the Mad Titan who he was and what his goals were. After a while, Thanos agreed to return Schmidt to Earth so he could help him in his search for the rest of the Infinity Stones. Schmidt then took on the identity Dale Russ and worked his way into the Pentagon in the following years, becoming the leader of the secret council of Thanos' Earthbound allies known as the Cabal.