Othello is a complex character. He is a man who is very much in love with his wife Desdemona, whom he has run off with and married behind her father's back. He is a high ranking general and is a Moor. He is well regarded and respected; however, due to his "dark" skin, there is an underlying element of racism, which Iago uses to its full advantage when he plots to let Desdemona's father know about Othello and Desdemona's marriage. Othello is brave and quick tempered and is vulnerable and gullible, as we find out when Iago convinces him that Desdemona is having an affair with Cassio. Othello tries to give her the benefit of a doubt, but after much plotting by Iago, whom he thinks is his friend, he is finally driven to obsessive madness in his jealousy. FYI: The phrase "green-eyed monster" (jealousy) was coined by Iago!
Othello, a Moor, a dark skinned warrior, has risen to rank of general in the Venetian army. The other officers are all white. Hence, it has created in others jealousy that Othello foolishly ignores. The manipulative Iago seeks to destroy Othello for reasons that Shakespeare leaves unanswered, but it is safe to say evil motivates him for evil's sake.
Othello secretly marries the white daughter of a Venetian senator, a mistake in that it turns others against him. A wiser man would know that others may be plotting against him; Othello doesn't take stock of those around him.
Iago manages to manipulate the weakened Othello into thinking that his new wife is having an affair with Cassio. Had Othello made the decision to marry Desdemona with the father's consent, he might not have had lingering feelings of his wife's ability to fool others. Iago is now free to manipulate others against the weakened Othello. Iago plants evidence of Desdemona's infidelities and has Roderigo planning to kill Cassio, right under Othello's nose. Yet, he refers to "his friend" Iago as "good" and "honest".
After having killed Desdemona and Iago is found to be the culprit of the whole sordid take, Othello does the only noble thing left for a soldier who has killed dishonorably: he commits suicide. A man of immense character and great flaws.
Othello is good character but quite innocent in this tricky world. He is very brave therefore, he is promoted to general. He has survived alone with the world and reached at the post of general being a moor but he is not aware of harshness of the world. Iago hated him for two reasons, firstly, due to racism, and secondly, othello promoted cassio instead of Iago however, Iago is a weak character from innerself. He is foolish, and do think from his own mind. He sees whats Iago told him to see, and believes what Iago told him to believe. He blindly trust on Iago, and in his blind trust he suspects on his beloved Desdemona who eloped with him without the consent of her father.