I, a minor character, fell into the Shura field of the heroine and the villain

Zhao Kang was transmigrated into a fantasy novel where the heroine is full of knives.
But he was just a supporting role master who died at the very beginning in the original novel.
It just so happens that his two disciples happen to be the hero and antagonist of the book.
In order to live well and to avoid the knife attacks in the original book, he paid too much.
His efforts include: preventing the villain disciple from turning evil and becoming the final boss. Helping the female cultivator...