the search was harder than they thought, only zombies or corpses can be seen roaming or laying on the ground, originally Li Xiang attended to ask someone about a big white castle floating in the air on top of the northern lights as described by Erha but now it might take a lot of time.
of course, he did not attend to take so much time finding people, first because Erha had previously mentioned to him that few people visited which already explain that his place is hidden and even if hr find people it's not necessarily that he will get his answer so rather then holding my expectations on one thing it is better to try everything, that way the efficiency will double and the timing will shorten.