Back when Poison Master Bai was younger, he had indeed suffered the betrayal from another.
It was a brother whom he had trusted deeply. Plagued with envy after learning about the existence of the Starweaving Art, the other party had discreetly switched a medicinal herb that he had prepared for the concoction of an extremely difficult pill, resulting in him being severely wounded in the affair. Not only so, the other party had even assaulted him while he was at a crucial stage in his cultivation, and that incident had nearly left him dead!
Even though he had exacted vengeance after he recovered, poisoning that wretched scoundrel to death with his own hands… the damage caused to his body was already irreparable.
It was due to such a wound that he had been trapped at the Primordial Spirit realm for so long, unable to achieve a breakthrough. This matter had become a huge regret in his life.
Millman: Sorry it's a little late; I was busy reading FMC (^▽^;)