This poison was colorless and odorless and extremely difficult to detect. Even if one had some understanding of medicine, they wouldn't be able to sense it immediately.
Only those who specialized in the Dao of Poison would instinctively sense the existence of poison.
Just like Xu Qing.
He instantly sensed this poison and frowned imperceptibly.
This was a poison he had never seen before. He couldn't smell the composition of the medicinal herbs inside and could only sense that it contained biological poison sacs. Moreover, it should be a mix of poison. Just one of them wasn't of much use.
'They still need the cooperation of other poisons to activate.'
Xu Qing's expression was as calm as ever but he was vigilant inwardly. Although he wasn't afraid of poison and his body contained even more potent poison, his cautious personality still made him flick his fingers slightly and poison spread out in the surroundings.
It was to protect himself.