Back Story: ~~~~~~~~~~ A war between wolves and cats broke out. Luna's mother was a part of it. She tried to protect her mother but ended up getting scratched badly, which would explain the blood. She ran back to her pack for safety, worried about her mother. When the war ended, she realized her mother had died. Now, Luna cries from time to time, visiting her mother's grave and realizing why the pack has been one member short and a bit more quiet.
credit to RainMoon