Robert Kirkman
Robert Kirkman took on the mantle of writer when Bryan Singer again could not commit to writing for the title. His run was originally scheduled for only nine issues, but was extended. Kirkman believed the Ultimate Marvel universe had developed a strong-enough footing to not rely on "'who's getting Ultimatized this week.'" He also believed that the Ultimate universe should retain its differences from the mainstream universe. As a result, he planned to introduce one character unique to the Ultimate universe and one character who already existed in the mainstream universe. These characters became the Magician and Lilandra, respectively.
Read more about this topic: List Of Ultimate X-Men Story Arcs