Some time back, I came out with this life and death theory on a bus trip to work. Simply put, every moment of your life to the nano-second, your death rate changes based on different factors. One of them is the change in death rate of your surrounding living forms.
NOTE: Some information may be wrong or inaccurate. Feel free to correct me by commenting or sending me a private message. Credits will be given. Thanks!
In this entry, I will provide the common sources of EXP and how they are stacked with one another.
Edit: New information updated. Refer to end of post for update logs.