21 Grams (Netherworld Messenger)
Rumor has it that the human soul weighs 21 grams.
Rex harvests souls to repay his debt.
He wants to build a suit of armor of equal weight for Ares to redeem his soul.
Wang Kenen harvested souls for an even stranger reason.
This reason seems so righteous on the surface that people often ignore its essence.
Concept: This is a two-way redemption story.