Where is this rash and most unfortunate man?

Lodovico
Where is this rash and most unfortunate man?
Othello
That’s he that was Othello. Here I am.

Demand me nothing. What you know, you know.
From this time forth I never will speak word.

Lodovico
Where is that viper? Bring the villain forth.
  Iago is brought forward.
Othello
I look down towards his feet; but that’s a fable.—
If that thou be’st a devil, I cannot kill thee.
  He stabs Iago.
Lodovico
Wrench his sword from him.
  Othello is disarmed.
Iago
I bleed, sir, but not killed.
Othello
I am not sorry neither. I’d have thee live,
For in my sense ’tis happiness to die.
Lodovico
O thou Othello, that wert once so good,
Fall’n in the practice of a damnèd slave,
What shall be said to thee?
Othello
Why, anything.
An honorable murderer, if you will,
For naught I did in hate, but all in honor.
Lodovico
This wretch hath part confessed his villainy.
Did you and he consent in Cassio’s death?
Othello
Ay.
Cassio
Dear general, I never gave you cause.
Othello
I do believe it, and I ask your pardon.
Will you, I pray, demand that demi-devil
Why he hath thus ensnared my soul and body?
Iago
Demand me nothing. What you know, you know.
From this time forth I never will speak word.
Lodovico
What? Not to pray?
Gratiano
Torments will ope your lips.