Pain is visualized as darkness around the creature. It is a state, when there is not enough of light energy.

When the creature's base energy capacity is not full, it starts feeling pain. And the pain makes the creature to look for the ways to replenish the energy.

Easy ways to replenish energy and feel better are:

Ways to get more pain:

Dark creatures suppress the feeling of pain, which changes their perception of the reality. They gradually stop perceiving the feelings of others, and all non-materialized energy becomes invisible for them.