voldermortsunbae:
I didn't get that part...it seems as if both tonics makes the person who drinks it suffer, but they become stronger later. so why omit the one ingredient...? wait, Elder Yue said that ingredient that makes a black line appear in your wrist was omitted by Wufeng, so maybe they removed it so that their spies aren't caught by the Gongs if they recognise it, since their poisons are only made for personal use and not for sale
Yes, the tonic makes the taker stronger. It's like battery recharge. Yun Que died at the hands of Wufeng because HYS retrieved her body.
So, Gong Hong Yu and the Elders knew about Master Yue and Yun Que so our Yue Lao never betrayed the Gong family.