Lore Theory: The Entity is a Spirit of Purgatory
So, looking over the character bios of Dead by Daylight I believe that I have an answer to what the Entity is: a malevolent spirit of Purgatory. Not just that, but all of the characters in Dead by Daylight are actually, well, dead.
Since we already have confirmed "in universe" for the licensed characters of Tapp, Bill, Laurie, Freddy, Amanda (Pig) and Michael Myers, not to mention the LITERAL DISMEMBERMENT of the Spirit, I think that there is a case for this theory. Some characters, though are easier to theorise than others. If you have a theory of your own to support this, then tell me!
Here's a shortened list of how I believe some characters died before being delivered to the Entity:
- Dwight: Alcohol poisoning
- David: Picked the wrong fight
- Claudette: Venom from animal in forrest - she was a botanist. Animals are not her forte
- Nea: Gang violence
- Jeff: Complications mixing alcohol and elicit substances
- Feng Min: Sleep deprivation/malnurition - people do literally game themselves to death
- Jane: Fell asleep behind the wheel, crashed
- Doctor: Experimenting on himself
- Clown: Total organ failure
- Hag: Blood loss/shock
- Nurse: Vehicle accident, thrown out of ambulance/crawled away
Bit of a morbid theory, but one that would certainly explain a lot of the happenings within Dead by Daylight.