The Imam.
 When the holy Imam reached the age of twenty, his father Imam al, Hadi passed away.  He then prayed over his father's body and declared being the next successor.
  The ruler at the time was trying to arrange for the holy Imam to go to Kuffa to plot his murder.  When the companions of the holy Imam heard the news that he will be traveling to Kuffa they feared for his life and began to worry.  But before the Imam headed for his journey he had left a letter to his companions advising them not to worry and the misery and troubles resulting from that ruler will be ending shortly.  Three days passed and the news spread that the ruler was overtaken and killed.  The succeeding ruler named Almohtadi Alaabassi, following the same path had a great deal of hatred toward the Imam.  He tried secluding the Imam and, and withholding people from seeing him.  But with God's will, his ruler ship didn't last long either.

 Though all the rulers tried to turn people against the Imam but they never succeeded.  On the contrary people loved the Imam and enjoyed being in his presence.  The holy had a brother named Jaafar.  Though being a sibling and having the same blood, Jaafar was ruthless and vicious.  He wasn't following the same path of Ahlul Bayt.  Jaafar would tell the ruler all the conversations that went on in the house.  He was an ignorant money who loved this world.

Death
Imam al, Askari’s leadership didn't last more than six years.  The holy Imam was sadly poisoned while eating and resulted in a life threatening illness.  The news spread that the Imam was ill.  Doctors all over gathered to try to cure the holy Imam.  But all they could do was watch another holy Imam die. He was sick in his bed for eight days until his soul was taken away.  He died year 260 hijra.  People all over came to pay their respects at the burial, then the Imam's brother Jaafar was preparing to pray over the body since it was announced that the Imam had not left any one after him.  As Jaafar was getting ready to pray, a small boy approached Jaafar pulled his dressing and said, "Wait Uncle, I have more right than you to pray on my father."

 The boy who was Imam al, Mahdi who is still to this day alive and Inshallah will appear when justice is needed, corruption is unlimited, and Allah, the Almighty commands him to.

Sayings
Imam al, Askari (a.s.) said, "Worship is not the quantity of prayer and fast, it's how much you think of your God."
 -The worst of people is he who has two faces and two tongues, praises his brother in front of him, and eats his flesh in his absence.
-Anger is the key to all evil.
-The heart of an ignorant is his mouth, and the mouth of a wise person is his heart.
 

This information was extracted from:
 1.  Kisasu Al-Abrar.