In more recent years he awoke, and piloted his ship to the nearest inhabited planet which happened to be Earth. He here came into contact with the Fantastic Four, who had been warned by Uatu the Watcher. The Overmind took over the mind of Mister Fantastic, and battled the Fantastic Four and Doctor Doom, who proved unable to stop him until the Stranger intervened and shrank the Overmind into a subatomic microverse on a dust mote, where he was left completely isolated with no available conquests, and went mad from the strain.
He was later discovered by another collective consciousness known as Null, the Living Darkness. In his current broken state Null managed to take control of him and sent him on a campaign against a parallel universe Earth inhabited by the Squadron Supreme. The Overmind, now a conqueror, mentally enslaved both the Squadron and this Earth's leaders, while posing as the U.S. president Kyle Richmond, and began construction of an interstellar armada to invade other worlds. When Hyperion brought the Defenders to assist him, they managed to free the Squadron. Meanwhile Null had leeched away the Overmind's mental energies, but yet another psychic composite entity, of 7 human telepaths, empowered by the assembled heroes, managed to defeat it, and came to inhabit the weakened Grom.
The Overmind then returned with the Defenders to their Earth. For a while this entity was welcomed into the Defenders' ranks, and the loose ends of the seven psychics's old lives were tied up. He assisted the Defenders in the rescue of Daimon Hellstrom from the Miracle Man. The Overmind grew uncomfortable and eventually left, while making them forget it was ever one of them. It tried to find a purpose by attempting to help Millwood, New Hampshire, a town of 800 people dying of chemical poisoning, by controlling their minds and making them ignore their ailments, in order to foster the illusion that they were well. However, the Overmind was convinced to let them be aware of reality rather than an illusion.
When the Squadron transferred to this Earth, the Overmind's original psyche was stirred into awareness and absorbed the telepaths into his own billion-wide whole. His psychic powers were replenished and his true mind reasserted itself. He once more mind-controlled and kidnapped the Squadron to take revenge against the Stranger by organizing a raid against the latter's laboratory world. He freed many of the Stranger's superhuman captives to fuel his enslaved ranks. He locked the Stranger in a stalemated mental battle. When several Watchers arrived on an unrelated business the Overmind was wrought by paranoia, believing the Stranger to have summoned them for assistance, inducing psychosis, and enabling the Stranger to capture him as a subject of study.
He later apparently managed to escape and declined participation in the Mad Thinker's quest for vengeance against the Fantastic Four.
His sole weaknesses are his inability to control Eternals of any race, and his schizoid composition can make his abilities weaken immensely when sufficiently stressed. The Over-Mind is susceptible to magic, the imposition of superior intellects and powers, and fatigue. Twice he suffered mental breakdowns, rendering him mentally vulnerable. He cannot impose his will upon the Eternals of any known alien races.
Additionally as a result of his alien physiognomy and metabolism, he possesses great superhuman physical strength, magnified sevenfold through psionic augmentation, and even more impressive speed, stamina, and durability. He is an experienced veteran of many wars, with considerable fighting skills.