Nyarlathotep, the Black Pharaoh, is in ancient conflict with other elder gods in his weight class, and seeks to enter the realm of Earth to rule over mankind. Unfortunately, he is prevented from doing so by a barrier that blocks eldritch deities from crossing over. To get around this, he breaks his soul up into thousands of pieces and seeds them into thousands unborn children. These kids become immortal avatars of Nyarlathotep called Nylanders, who do battle with each other over the centuries through one-on-one engagements to the death. When one is killed, the other "eats" the loser and gains their power and memories, absorbing them into themselves. When all pieces of the deity have joined, Nyarlathotep will become whole within one body and would be reborn on the mortal plane. In the end, there can be only one.
As each child is killed/destroyed, the remaining Nylanders' gain that power equally. There is no single benefit to the one who made the kill. As the Nylanders are killed over the centuries, the rate of power absorption would increase each time, with the final two battling being the strongest of their brethren.
As power is shared out over remaining warriors to prevent a major shift in balance toward one individual, this battle is spread out over many millennia. This forces Nyarlathotep's assembly to take longer than what is necessary. What benefit would a deity gain from slowing down his conquest of the mortal realm?