Wang Wei absorbed the two floating orbs inside his body, and as soon as he did so, two giant figures appeared behind his back. These two figures were his grandfather and father.
The two gray orbs that he absorbed were an application of the [Fate Stealing Technique]. By copying and storing the fate of someone else, Wang Wei can temporarily use their powers.
As the two most powerful people that he knew, Wang Wei copied their fate. When he developed this technique, he wanted to copy his wife's fate. Unfortunately, she was too powerful for him to do so.
Additionally, this technique required a lot of time, consent, and aid from the person whose fate is being copied. Plus, it seems to work better with people that are closely related to the caster.