Is Abu Bakr preferred over the Mahdi, and what are the characteristics of the Mahdi, and who are the best martyrs in the sight of Allah?

Scholars are in agreement that Abu Bakr Al-Siddiq is the best of the Ummah after its Prophet, so he is superior to the Mahdi. As for the Mahdi, he is from the Prophet's household (Ahl al-Bayt), with a broad forehead and a prominent nose. He will fill the earth with fairness and justice and will rule for seven years. As for the best of martyrs, he is Hamza ibn Abd al-Muttalib, followed by the man who stands before an oppressive ruler, commands him to do good and forbids him from evil, and is then killed.