KappaKappas don't have souls on their own, they can steal souls of other sentient creatures, killing them in the process. Stealing a soul will result in kappa receiving the years the previous soul owner had, prolonging their live span; kappa can survive very long after stealing a soul of a child, but stealing a soul of an elder adds but a few years. In order for new kappa to be born, a soul must be supplied. In theory, kappas are immortal - as long as they keep stealing souls.
This puts kappa in a moral dilemma - is prolonging your life worth killing others? Is prolonging your life worth not prolonging the life of other kappas or denying the creation of a new kappa? It's probably this dilemma, why kappa society is very pious. Their religion mostly focuses on the concept of self-worth and the worth of others. They have a strong sense of morality.
Currently, kappas ban others from stealing souls to prolong their lives - with a few exceptions, rewards for extraordinary actions. Kappas try to negotiate with other empires, to receive convicts as sacrifices - so they can use their souls for reproduction. They try to be a peaceful nation, even though they are looked down upon by other empires for their soul-stealing powers.
Separatist kappaEnemies of other kappas, these kappas decided, that prolonging their lives is worth taking the lives of others. They are typically slavers - raid a village, get slaves, work them to near exhaustion, harvest them for souls, repeat. Separatist kappas can cast magic using the power of their harvested souls. Normal kappas would never do that, as it takes precious years from their life spans. Thanks to magic, separatist kappas are very powerful and feared fighters.
