Lin Wu knew that there was no way he would be able to put a servant imprint on a human. The technique that he had was only made for beasts and even the system couldn't modify it enough to make it work on humans without more data.
If he wanted to do the same with the humans, he would need to find a slave binding technique and he was pretty sure they were forbidden. Of course, they could still be found in the market and even in the sects, but the question was that of access.
He couldn't just waltz straight into the places while being in his form of worm and neither could he order Shirong to do it directly. Thus he either had to wait on his luck to bring that to him or he could go about this in a different way.
Lin Wu had seen the method by which the Formations array of the tomb had passed the inheritance to him and he was thinking of using that as a back door to put an imprint on Wang Xiong.