Who is al-Ashtar, and did he play a role in serving Islam, and was he among those who killed our master Uthman, may Allah be pleased with him?

Al-Ashtar is Malik ibn al-Harith al-Nakha'i, a courageous, eloquent leader known for his ferocity in battle. One of his eyes was gouged out at the Battle of Yarmouk. He was among those who opposed Uthman, may Allah be pleased with him, and participated in his siege, though he did not directly kill him. He stood by Ali, may Allah be pleased with him, in his wars. He died in the year 38 AH, poisoned on his way to Egypt, where he was appointed governor.