i just finished the war againts the empire and a courier gave me a inheritence letter but i travel alone and no one i know died but this person named angrenor who i dont even know who he is sorry for my loss who is he no loss of mine if this is a bug.

No it's not a bug, that's just what happens sometimes with NPC's. He was probably a random killed in a dragon attack or during the battle for solitude. Not a bug, don't worry