If it were anyone else, they obviously couldn't control Li Cheng's Sword Spirit so easily. After all, Summoning Class familiars are very personal things.
No matter their disposition, all familiars have a unique Heart Spirit imprint. Even if someone knew the method to control them, it would be impossible.
But Li Shifan was an exception. This was because Li Cheng had transformed from a ghost into a spirit, and his own Cultivation hadn't yet reached the stage of the Gathering of the Three Souls. Therefore, rather than calling him a ghost now, it was more accurate to say he was a special kind of Artifact Spirit.
After all, ghosts have their own autonomy, whereas an Artifact Spirit has none once it acknowledges a master. Li Cheng was precisely one of these—an Artifact Ghost with no autonomy of his own.
