Sibling Self-Hatred

 Immortals die to self-hatred. The hatred manifests as suicide of one kind or another.

 The atomized debris of the former immortal plummets down here, into the underworld, where it is born as mortal brother and sister.

 Siblings are 50% identical, as similar as parent and child, as similar as you can possibly be short of identical twins. This is precisely why they have such difficulty getting along. The sibling reminds you of yourself. You hate yourself, so you hate your sibling. You get sibling [[rivalry]]. You get squabbles over inheritance. You get Cain. You get patricide and matricide.

 You get immigration. If someone similar reminds you of yourself too much to be tolerable, why not grab someone as different from you as possible?
 Of course you still can't get along. Now because you're too different and have neither the capacity nor the desire to understand each other. But hey, at least it's a different flavour of repulsion. 

 

 Any level of self-hatred is unsustainable. The point of hatred is to motivate destruction. If the destroyer hates itself, it turns the destruction on itself, and what, exactly, is going to resist? Indeed that's how the immortal dies in the first place. They voluntarily absorb Death, integrating her with themselves, and subsequently the outward world moves into alignment with the inner. 

 Problem: self-hatred is insane. It's supposed to motivate self-destruction, therefore, it doesn't. 

 The self-hating mortal suppresses their self-hatred to avoid immediate annihilation, but being reminded of it by a brother or sister or parent risks breaching the containment. They must attack precisely that which is more similar to themselves.
 Of course if breaching it were that easy they wouldn't have made it to term and been born in the first place. There's no need to be concerned. Self-hatred is insane.

 You try to assimilate the immigrant, but if it works, you start hating them, and need new foreigners. Who you hate, just like the last foreigners, because they're different. Do you learn nothing? Do you do it precisely because you hate it? Likely, both, if self-hatred has driven you truly mad. 

 The self-hater looks at the world through the haze of hatred they create around themselves. Naturally, they hate everything they see.
 This is what they want. All these awful things clearly exist to punish the atrocious one they hate the most - themselves. 

 Because self-hatred is insane and unsustainable, it violently conflicts with Darwin. Automatically selects against itself. Which conflicts with the insanity of self-hatred, trying to preserve self-destruction. Result: "The spirit is willing (to self-annihiliate) but the flesh is weak." Humans get shackled by Darwinian impulses, which force them to behave in a minimally viable way. 

 Humans hate each other, but have sex anyway. They hate the resulting kids, but they keep having sex anyway. They hate the resulting kids, but they feed them anyway. They defend them against maiming anyway. The flesh forces them to, since any subspecies that didn't enslave the members this way has long ago been properly annihilated. The desire for the physical to converge on the spiritual in this field is constantly thwarted, because its success is self-defeating. If there are no mortals to act as containers for the debris, new mortals must arise to form containers for the debris.
 By their mere existence, mortals run up karmic debts. However, by ceasing to exist, they also run up karmic debts. Paradox. Madness.