Dark, that was all he could remember at his birth some time ago. The dark was quiet and comforting, but it had lacked something. It had lacked life. There had been nothing for the god of Death to watch over, there had been no reason for him to even exist. Would he have faded away had there been no life to enter the world other than himself? Probably not, but it would have been boring.
Mortum's birth itself wasn't a particularly spectacular thing. No mountains shook, no oceans formed, nothing physically changed. There was however, something that marked the birth of Mortum. It was a feeling, one that would have caused paranoia in mortals had any been around to feel it. This feeling brought the gift of death to the world, the ability to die.
Mortum had, strangely, been born with clothes on his body. He had been born with quite a bit of knowledge, knowledge concerning who he was and why he was there. The god of Death however, had been very young and had little control over his power. The ground wilted where he had walked and would never hold life again, but that was in the past now.
Some time later
Time had passed since the birth of the young god and wisdom was brought with it. The god learned to restrain himself and simply wandered the strange planet he was on, no longer leaving cursed ground in his wake. Mortum had come accross strange creatures in his travels, creatures which seemed to hunt or be hunted. Mortum had watched a fierce animal take down a weak animal, he had watched the life drain out of the weaker animal and its soul leave the restrictions of a body. This was death, Mortum could tell that without even having to think about it. What had happened seem so obvious to him, but his acquiring of this knowledge didn't nor did the acquiring of his other knowledge.
The soul of the weaker animal appeared lost when it left its body, for it did not know what to do. Mortum did not know if all beings were like this at death, but he decided to fix the situation. He walked up to the soul calmly and put his hand on its ethereal body. It took him a second to decide what to do, which ended up being to send the dead soul to where it was meant to go. The soul had gone to its resting place, wherever that may have been.
A few minutes passed and Mortum finally noticed that the hunting animal had finally left. It hadn't seen nor sensed him, for he had decided it to be so.
He decided that he couldn't collect the souls of every dead being and decided to create a new creature, one in his own image. From this need stemmed a creature of death: a reaper. He made two reapers, one male and one female. They had black auras, sentience, knowledge, wisdom, and power. They wore hooded robes and had an invisibility to those who were not dead nor godly. Their presence could however, be discerned with a spell of revealance, but that information is for a later time. The two held scythes, each capable of sending souls to their destined places when in the hands of a reaper or animating the bodies of the dead if need arises.
"Libitina," He pointed towards the female, naming her and giving her an identity. "Letum," He pointed to the male, the one which would later become his Avatar. "You are the creations of I, the God Of Death, Knowledge, and Wisdom." He paused for a second, "My name is Mortum and you are the first reapers." They already knew what reapers were, for they had been born with the knowledge of their reason for being. "Now go, do your duties and send the souls of the dead to their final resting place." Mortum sent them away.
Perhaps he would fine similar to him or perhaps he wouldn't, it mattered not. It only mattered that he continued walking until he met something.