Noragami2014

Yato:
Master and Regalia share mind and body. I get stung every time Yukine gives in to temptation. That's how things work for Regalias and their masters.

Iki Hiyori:
Then, does that mean Yukine got stung too when you swiped some of my father's drinks?

Yato:
Nope. The pain from deranged thoughts only goes in one direction - from Regalia to Master. Regalias used to be people, and people sin. Resentment, fear, envy, desperation, sadness, greed - these and countless other things give rise to temptation. The sin of acting on it turns to pain, which is how we learn, via Regalias, what is right and wrong.