To be fair, with Su Li’s current strength, killing a "Nine Tribulations Loose Immortal" is not difficult. However, if a Nine Tribulations Loose Immortal were to launch a soul attack first, even if Su Li could still kill them, he would have no way to intercept that soul attack afterward. This is because soul attacks cannot be defended against using the power within one’s own body. To a certain extent, the latter can only be considered a "material attack," which is entirely different from a soul attack. The two can never intersect.
But now, with the mysterious and unpredictable "incomplete iron fragment," things are different. Even if a Nine Tribulations Loose Immortal who has cultivated a Soul Gathering Body were to launch a soul attack at him, he could summon the fragment with lightning speed to intercept it, allowing the iron fragment to devour the attack entirely. In that way, the opponent’s soul attack wouldn't even be able to touch him.
"Third Uncle... thank you."
Chapter 2558