The identification of a top-tier martial world force is much clearer than that of a second-tier, they must at least have more than five martial artists in the Divinity Transformation Realm, or one martial artist in the Fusion God Realm. This is considered a top-tier force, such as the Li family of Longxi, they are this type of top-tier force, and they are relatively strong at that.
Asking Su Xin to annihilate five second-tier forces meant that he would have to fight against martial artists of the Divinity Transformation Realm.
And dealing with those martial arts sects that have more than ten martial artists in the Innate Divine Palace Realm would not be easy, unless Su Xin was willing to use his Villain Value to exchange for Four-Star Level martial arts. Only then could he withstand more than ten martial artists in the Divine Palace Realm.