Upon his arrival, Kaos landed in a very ancient part of Skylands and inadvertantly reactivated the , quickly learning that if he could acquire something known as the Iron Fist of Arkus, he could not only reactivate the entire army of Arkeyan robots, but also command them. With that kind of power, Kaos would be unstoppable. Despite the Skylanders' and the Giants' efforts to stop Kaos, the evil Portal Master was able to reach the and gain hold of the Iron Fist of Arkus, transforming himself into a large Arkeyan robot before using the Iron Fist's power to resurrect the Arkeyan army.Before he could begin his world conquest with his Arkeyan army, the Skylander confronted Kaos to stop his evil plan, only to discover that the now Arkeyan Portal Master was impossible to stop unless the Iron Fist of Arkus was removed from his grasp. With the help of and , the Skylander was able to remove the Fist of Arkus from Kaos' grip, returning the evil Portal Master to his normal form. After losing the Iron Fist, and soon afterwards the Arkeyan Conquertron, Kaos returned to his where he revealed to Glumshanks that he had at least 37 more plans to take over Skylands. The evil Portal Master laughed evilly, only to be confronted by his moments later.
Kaos forced a weather wizard named into following his orders, threatening to cut the wizard's precious Amazing, Fantastic, Incredible, Suprising, Unfathomable, All-Coloured Rose if he didn't do what the evil Portal Master commanded. He used Hurrikazam to kidnap the undead inhabitants of the in order to drain them of their undeadliness and store it up in a tank of Undead energy to shower every island of Skylands with undead rain showers to turn the living into undead as well as to destroy the other elements. Without Hurrikazam's notice, Kaos operated the wizard's weather machine to cause unnatural harmful weather conditions throughout Skylands.However the Skylanders, , and were able to uncover his devious plan, but became captured by Hurrikazam. Kaos ordered the wizard to drain the Skylanders of their element, but Hurrikazam refused despite losing his colorful rose. The evil Portal Master tried to proceed with the draining process, but accidentally released the Skylanders. Just as the Skylanders had Kaos cornered, Hex suddenly trapped Cynder and Zook in her bone fortresses, revealing that she had switched sides, now serving Kaos. Hex allowed herself to provide Kaos with her powerful Undead energy, claiming that she was tired of being feared and longed to be normal again. Kaos eagerly began the procedure, however the machine was overloading with Hex's power, which the elf sorceress planned all along and never actually defected to Kaos.
Kao's Mom later came to Kaos' Kastle in person to help her son in his plan, also bringing a few friends, including the evil puppeteer, . After the Skylanders defeated Kaos and kept him tied up by ropes, Kaos' Mom interrupted the volcano celebration and kidnapped Tessa, and also rescued Kaos. The Skylanders, Flynn and Sharpfin embarked on a mission to save Tessa, infilitrating Kaos' Fortress before confronting the mother of all evil herself. Just before her battle, she appeared revealing herself as a true dark Portal Master and that her power knows no equal to Kaos. She was soon defeated by the Skylanders when her own dark magic rebounded off Kaos' mirror, and the force of that power pulled and trapped her within said mirror. Kaos' Mom soon called Kaos for his assistance and soon discovered that Kaos went on to the Cloudbreak Volcano to proceed with his own evil plan. Despite being betrayed, Kaos' Mom praised her son for his treacherous nature.