Togaro was a tyrant who lived on the microworld of Mita where he sought to overthrow the king and queen of the realm. Fearing for their daughter's life, they sent her to Earth where she was adopted and named Dianna. Learning of this by the time Dianna was an adult, Togaro led his minions to the surface world, where they used their size-changing drugs to grow to gigantic size and terrorize the Earth. This attracted the attention of Captain America and Bucky who, coincidentally, were friends of Dianna in their civilian guises of Steve Rogers and James Barnes.
Defeating Togaro's minions, they soon learned that Dianna went missing, and they were confronted by Togaro himself, who warned them and Dianna's brother Frank to stay away from Bird Nests' Island. They went anyway, and learned of Dianna's origins. Returning to Frank's cabin to make more of the size-changing drug, they were unaware that Togaro (having shrunk in size) had smuggled himself along on Bucky's boot. Seeking to stop them from traveling to Mita, he used the drugs to grow a cockroach to human size, but the creature was fought off by Cap and Bucky. Using the size-changing drug, the two heroes chased Togaro into a knot of wood in the hardwood flooring of the cabin, but the villain managed to escape them and retreated. He once more hitched a ride back to Mita, hiding on Bucky's body for the trip, and almost succeeded in killing them by again growing an insect in size -- this time an ant.
On Mita, Togaro then kidnapped Bucky and the Mitan known as Ailma and set a device that sent Mita hurtling into its own sun. He and his men then retreated to the cracks of the rock where the atomic world of Mita existed. There, they were followed by Captain America, Dianna, and Frank, who rescued Bucky and Ailma and returned to the surface world. Togaro followed after them and took his size-changing drugs to grow to massive size. Captain America matched him in size and during their final struggle, Togaro was knocked down and fatally struck his head on the side of a cliff and died, ending his threat once and for all.
Togaro had size changing drugs that allowed him to shrink to microscopic size or grow to titanic heights.