In his past life, the unlucky ones were other Players who would find themselves suddenly being attacked by a huge group of Ice Trolls while they were on a rampage that would them up from dying. It was a rather terrible event that had led to many deaths in the past of many Players in several other teams. It was a rather dangerous thing that would cause many other Players to end up dead.
The Ice Trolls were one of the higher-leveled enemies that were capable of using magic as a skill, and they were enemies that had high regeneration as well, so even decently-leveled team Players could wind up being dead if they were not careful and ended up being idiots.
Most groups often had different members in the team, like the typical Fighter class, a Healing Mage and the Thief... but in the face of High Leveled Enemies like the Ice Trolls, they would end up getting killed due to the difference in levels and in numbers too.