In a flash, this combined in my head with a conversation I had with lensedqso about her playing touch football with her cousins and it got me thinking.
What if the dead are allowed to choose a team, like in a pickup game of football? Imagine, if you will, you're dead, and your day comes around to pick a companion. Who do you pick? What are your motivations? If theoretically you are allowed to pick, say one person every year after your death, do you spend all year thinking about who it will be? Do you pick someone you love who's suffering so you can end their pain? Do you pick someone you love because you want them with you? Do you pick someone to cause pain to someone else? There are so many possible motives.
Maybe there's a quota, a certain number of people have to die per day. Maybe it's subdivided by region, or religion, or creed who some other obsure metric that only makes sense in the afterlife. Maybe you don't get to pick who dies, but you can exchange a life for a life, like an equal value exchange calculated by whatever metric they use to evaluate these things. That would allow you buy more time for a loved one or bring one to you sooner.
Maybe it's talent-based. You pick someone for death based on the skills they can bring to your crew.
Well, honestly, it's no worse an explanation than some others I've heard.