In the advent of the Heroic age, Kro attacked New York, trying to incite fear in the human population of the incoming Celestial judgement. He battled the Eternals and agreed a truce with his old lover Thena, showing themselves to the modern world. He tried to reconciliate with Thena, bringing her to the City of Toads of Lemuria. She was treated as royalty, but she become horrified with many of the Deviants practices, like the purge of the very monstrous deviants, and the Gladiator's fights to the death. She took the Deviant gladiators Ramsak and Karkas, and fled Lemuria, leaving Kro angry. He battle the Asgardian God Thor, when he went to the Deviant city under New York, to rescue some of the Eternals. Kro was left behind by Brother Tode, who escaped in a flying pod. Kro also took part in the ill-advised assault in Olympia. The Deviant's aristocracy, led by Brother Tode, kidnapped the Eternals and intended to disintegrate them. Kro tried to save Thena, but she rejected him again. The hero Iron Man (James Rhodes) rescued the Eternals and helped them defeat the deviant invasion. Then the Eternals transformed the deviant's aristocracy into a synthetic cube, killing them. Thena saved Kro, and he was the only survivor of the failed attack.