After investigating the Thunder Restricted Area and learning from Xue's senses about a being within—a Demon Race member, possibly with the White Tiger Bloodline, on the verge of reaching the Harmonization Realm—Jiang Qiu had returned to a city controlled by a Thunder Clan to focus on deepening his fusion. The location was convenient for gathering intelligence from the clan, and it wasn't too far from the Restricted Area.
When they had been gathering intelligence, it was Xue who had obtained most of the information. She seemed to possess an Innate ability to sense the presence deep within the Restricted Area's barrier, an ability Jiang Qiu himself lacked.
Of course, this wasn't a major issue. Most of their senses were shared, so as long as neither of them deliberately shielded their Soul, no information could be hidden. And since deliberately shielding one's Soul came at a great cost, it was extremely difficult for even people from the Outer Realm to interfere.
