What is the poison of a red line in martial arts novels?

It is datura poison.

Mandala is also called mandala, manda, manza, manda, Sanskrit, mandala. The free translation is Mandala, with the original meaning of being surrounded by a circle or gathering. It refers to the gathering place of all saints and meritorious deeds. Offering mandala is the most complete and ingenious way to accumulate merit and wisdom. Offering to the entire universe in the form of mandala is the fastest, simplest, and most complete among many methods.