Grim reapers have been personified by our ancestors and the present as black cloaked beings carrying a scythe and bringing death. But unbeknownst to them, they were just those who accompany the dead to their final resting grounds, that is, to avoid wandering souls. But of course, sometimes souls tend to wander further away from the reaper assigned to collect them.
There are five types of reapers.
First, is the White type. White reapers are the strongest and most beautiful of all reapers. They are those who collect the most beautiful souls that either died of old age, in sleep, or of heart attack. Every soul they collect are said to have found no regrets upon parting from the mortal realm. Which makes the white reapers extra special. They could disguise themselves as a white dove, a white moth, or a white butterfly. They often visit the soul that is about to die at least twice. (Following the human would make him seem to sense his own death, and would by then say their goodbyes before they actually die.)
Second, is the Red Type. Red reapers are the fiercest and most enigmatic of all reapers. They are always serious and is the closest to resemble the reapers we often heard in myths. They do carry a scythe, and often wear gloomy outfits. But they do not wear cloaks. They are responsible for collecting the souls of those murdered, regardless if they are innocent or not. They say that when you smell an awful and strong scent of cinders, one is nearby.
Third, are the Yellow type. Yellow reapers are those who collect souls of those that died because of animals. They could communicate to animals and are the friendliest of all reapers. They could disguise themselves as any animal they would like. If you hear a noise of an animal even if you don't have one and none is nearby your location, a yellow reaper is playing tricks on you for fun.
Fourth, the Purple type. They are related to the yellow type. And could shift themselves into any animal they would like as well. The only difference is that they collect the souls of animals. Not those killed by them. They are said to be even friendlier, but not as mischievous as the yellow type. They are the last thing your pet animal sees when it dies. And they say that when an animal is either surprisingly calm or distressed and freaked out, one is watching over them.
Lastly, is the Gray type. The gray reapers are responsible in collecting those who died by accident or by surprise. They often collect the saddest souls as they did not expect their swift death. Most of their clients are often upset, and haven't fully accomplished their main goal in life yet. Gray type reapers are one of the most hard working reapers as accidental deaths grow rapidly over time. Like the white type, they would follow their victims twice before the actual death happen, and when dead, would dutifully collect their gloomy souls.
If you are wondering who collect the souls of those who killed themselves, well, there is none. As even the reapers consider them a very filthy soul for wasting God's borrowed life while others fight for it. So most of them wander the mortal realm, helplessly and angrily as they never did truly found peace.
In some cases, those that have committed a very very terrible sin and died either by murder, in sleep, by an animal, or by killing himself, is also not collected if its soul is already very corrupt. So in collecting a soul to be again used to create another being, the reapers must consider if it is 'worthy'.
And the most worthy of worthy souls are gifted in the next lifetime to either be a mortal with a great profile, or a supernatural with immortality and great power. That's right. Even a mere human soul could become a reaper if worthy enough...