Adamus Phillida's Bodyguard is an Imperialguard who is assigned to protect Adamus Phillida after retiring from a successful career in the Imperial Legion, to the city of Leyawiin. He was given a bodyguard to ensure nothing bad would happen during his retirement.
The bodyguard follows Phillida around, not actually having to do anything until an assassin from the Dark Brotherhood is hired to kill Phillida.
Because the bodyguard failed his duty to protect Phillida and deemed himself a failure, he committed suicide. His body can be found inside the Leyawiin City Watch Barracks, along with a suicide note.
Ocheeva tasks the Hero to kill Adamus Phillida as he has pledged his life to destroying the Dark Brotherhood. Now that he's retired, it's time to destroy him, and send a message to whoever follows him that the Brotherhood is not to be trifled with.