After defeating Radahn and taking his Great Rune, Ian would also take his soul. According to the original timeline, after Radahn's body died, his soul would return to the Erdtree, and Miquella would summon it forth. She would then place that soul inside Mohg's body and resurrect Radahn as her consort after becoming a god. But Ian took the soul not only to stop Miquella, but also to extract a specific memory from him.
Radahn had once performed a ritual, using Gravity Magic to seal the stars. This greatly weakened the Outer Gods' ability to interfere with the Lands Between, and Ian's plan happened to require that ritual. After completing this, Ian's next target would be Nokron, the "Eternal City," where he would obtain the Fingerslayer Blade.
Nokron was an ancient civilization that had ultimately betrayed the Greater Will and developed a weapon intended to destroy the Greater Will's watchdogs on this planet—the Two Fingers. Their betrayal was discovered, and the Greater Will sent the "Naturalborn of the Void," Astel—a malformed star transformed into a monster—to destroy Nokron and the Nox People.
Once the Two Fingers sensed Ranni's intentions and controlled Blaidd, Ranni would ask Ian to help her deal with Blaidd. In exchange, Ian would demand that she hire Black Knife Assassins to infiltrate the Roundtable Hold and kill the ruling Two Fingers and Enia, completely severing all ties between the Greater Will and this world.
With greater freedom, Ian would continue advancing his plan. He would first head to Leyndell, Royal Capital, kill Morgott, the Omen King, and take his Great Rune. Next, he would defeat Maliketh—like Blaidd, he was Queen Marika's shadow—and take the Rune of Death. This battle was destined to be extremely fierce, because if Maliketh so much as touched Ian's armor once, he would