Roderigo attacked Cassio but did not kill him. Iago had intended that Roderigo would kill Cassio and then Iago would kill Roderigo. In the scenario you are suggesting, Roderigo is a much more successful fighter than we thought and manages to kill both Cassio and Iago. He would then no doubt have been charged with killing them and might offer in his defence how Iago had conned him out of all his money. Emilia would be able to tell her story and live and it would certainly corroborate what Roderigo would say. Unfortunately none of this would come in time to save Othello or Desdemona, who would both end up dead in any event. Since Cassio is dead, someone else would have to be governor of Cyprus.
roderigo dies
Roderigo.
Cassio fell to the ground and cell out for help
He killed Roderigo.
Othello will recieve the blame for the attack on Cassio because roderigo has died and everyone already knows that Othello has enough hatred on cassio because of his jealousy.
roderigo dies
Roderigo.
Cassio fell to the ground and cell out for help
Iago uses Roderigo's unrequited love for Desdemona and his jealousy towards Cassio to spark his interest in his plan to discredit Cassio. He convinces Roderigo that by helping him, he can win Desdemona's affection and thwart Cassio's advances towards her.
He killed Roderigo.
Othello will recieve the blame for the attack on Cassio because roderigo has died and everyone already knows that Othello has enough hatred on cassio because of his jealousy.
Rodrigo is stabbed by cassio and killed. Bianca does not die.
Iago does the plotting alone; Roderigo is his dupe and has no more idea how he is being used than Cassio does. In Act II Scene 3 Iago makes sure both are drunk and quarrelsome and then eggs Roderigo on so Cassio will fight with him, thus ensuring Cassio's dismissal. In Act IV Scene 2 Iago lies to Roderigo, telling him that Othello is being sent to Mauretania where Roderigo will never have a chance to see Desdemona. Iago tells him that this is only possible because there is a competent replacement for Othello on hand in Cyprus in the person of Cassio. Get rid of Cassio, and Othello must stay in Cyprus. In this way Iago dupes Roderigo into trying to murder Cassio in Act V.
He thought Roderigo already had.
Iago has been systematically conning Roderigo out of his money, saying that he is using it to try to get Desdemona to dump Othello and go for Roderigo instead. Iago knows that Desdemona will never do this, and has been simply pocketing the money. Roderigo is starting to catch on, so Iago feeds him the same line about Cassio and Desdemona having an affair and sets Roderigo on to murder Cassio. His objective is to get rid of both of them. Roderigo does stab Cassio, who Iago takes for dead, so Iago kills Roderigo himself.
Iago wants to create chaos and manipulate those around him for his own gain. By instigating Roderigo to provoke Cassio, he can further his own schemes and deepen the rift between Cassio and Othello, furthering his agenda to destroy both of them.
Iago's plan is to make Cassio drunk and get him into a brawl that will ruin Cassio's reputation and cause him to lose his position. He urges Roderigo to provoke Cassio "to put our Cassio in some action/ that may offend the isle." As usual,Roderigo is duped by Iago's manipulative words and agrees to do this, even though all he ends up with is a sound beating from Cassio. Iago, however, succeeds in getting Cassio dismissed from his lieutenancy to Othello, which plays in toIago's master plan to ruin Othello.