Mahdi Will Not Shed Blood
Hazrat Mahdi (pbuh) is someone who avoids war, a man of peace. Hazrat Mahdi (pbuh) will cause the moral values of the Qur'an to rule the world through love, not through war. The fact that Hazrat Mahdi (pbuh) will bring about the rule of the moral values of the deen (the religion of Islam) through peace and love, which represents one of his main distinguishing features, is described in the hadiths:
"People will seek refuge in the Mahdi (pbuh) as honey bees cluster around their sovereign. He will fill the world that was once full of cruelty, with justice. His justice will be as such that HE WILL NOT WAKE A SLEEPING PERSON, NOT EVEN ONE DROP OF BLOOD IS SHED. The Earth will return to the age of happiness. (Al-Qawl al-Mukhtasar fi 'Alamat al-Mahdi al-Muntazar, p.29 and 48)"