Pain is often described as a negative feeling, something any sane person would try to avoid at all costs. Some would kill or even betray their loved ones only to avoid it, while others would risk their own lifes out of fear of it.
But that didn't apply to Ryu, not in the slightest. Right now he found himself trapped inside his own mind in a blank space where nothing could be seen or felt. For him, pain was a reminder that he was still alive, that there was something he needed to do in order to survive.
Did he accidentally trip over a root and lose a health point? the pain he felt that day allowed him to continue, to keep walking knowing full well he couldn't afford to stay put in a dark forest.
What about the time he got bitten by a jackal? that pain was almost unbearable, yet, it reminded him that he needed to clean and dress the wound appropriately or he might lose a limb.