Zhang Hanyu's face instantly darkened when he heard what his old master said. Even though he knows that his old master is just cracking a joke to ease his (ZHY) tension due to Tang Lele being missing right now after claiming that Tang Lele is his responsibility, Zhang Hanyu still felt annoyed by his old master. He knows that his old master is a carefree old man as his children are all already have their own families. So, this carefree old man would often crash into his home.
Fortunately, despite his (ZHY) is all highly-educated individuals, they still believe in metaphysics since the world is vast, and most of it especially the ocean is unexplored. So, they warmly welcomed him to their home. They even curiously asked the old man about metaphysics, how it worked and such. In short, the Zhang family is very open-minded. Even if they found out that Zhang Hanyu might be asexual, they didn't care. They only cared for their children's happiness.
