Reapers were granted the right to live again. But with that right came a task.
The task was to kill as many zombies as possible in Hell. That was what I used to think, but now I know that was an oversimplification.
Our job wasn't just to kill zombies. It was to capture and contain as much spirit as possible. We were antibodies raised by the World Tree to cleanse itself of negative emotions. Therefore, any Reaper who remained either a Wraith or a Phantom was only doing half the job.
As far as I could tell, a Wraith had a capacity of 100,000 souls. If he went beyond that, he would go insane. For Phantoms, the limit would be 3 million, give or take. This meant that a single Phantom was the equivalent of 30 Wraiths.
But that was only if each Phantom carried 3 million souls. Fortunately, since the Reapers were greedy bastards, few of us would turn down the opportunity to receive souls. We used them for skills, death resonance, and most importantly, cash.