The troll's business thrived because—
If players from the main world saw an injured ally, they would usually just take them back.
But among the Swallowing Heaven players, there were no kind-hearted individuals.
Injured players and demons could mostly only wait for death, or they might have a "comrade" come along and finish them off.
So now, during the [Anti-Expansion] event, killing allies would yield no rewards and even incur penalties. This meant that those Swallowing Heaven players and demons, who would usually enjoy causing trouble for others, had to leave their dying comrades on the battlefield in a pitiful state.
Naturally, Sterl was not actually injured; he was merely pretending. By spending 800 purple gold coins, he managed to seamlessly integrate himself into the ranks of Hell.
Otherwise, a normal pathway to join the Hell faction at this moment would require a review and approval under the divine-level demons.