Malchus

Who did Peter strike with a sword, and what mortal blow did he inflict?
He “struck the high priest’s servant, and cut off his right ear. The servant’s name was Malchus” (John 18:10).

What does the detail, "right ear" (John 18:10) imply about this account and Malchus' attire?
The precision - “right” ear - points to an eyewitness account and that Malchus wasn't wearing a helmet, which means he most likely wasn't wearing a body armor either.

Why did Peter attack Malchus instead of Judas Iscariot?
He probably just swung at the man nearest to him, who happened to be Malchus, the unprotected and most probably unarmed "servant" (the original Greek word, δουλον (doulon), can also be translated, "bond-servant" or "slave") of the "high priest" (John 18:10).

To what "cup" is Jesus referring?
See John 18.

What else did Jesus say to Peter when he cut off Malchus' ear?
"Put your sword in its place, for all who take the sword will perish by the sword. Or do you think that I cannot now pray to My Father, and He will provide Me with more than twelve legions of angels? How then could the Scriptures be fulfilled, that it must happen thus?" (Matthew 26:52-54)

How many angels would be in twelve legions?
12 x 6,000 = 72,000.

What kind of damage would they be capable of?
Isaiah 37:36 records one angel killing 185,000 soldiers in one night: "Then the angel of the LORD went out, and killed in the camp of the Assyrians one hundred and eighty-five thousand; and when people arose early in the morning, there were the corpses - all dead." So 72,000 angels could have killed 13 billion soldiers.

What could Jesus have done?
Wipe out not only the 600+ who had come to arrest Him, but everyone on the earth.

Instead, what did Jesus do?
He healed Malchus: And one of them struck the servant of the high priest and cut off his right ear. But Jesus answered and said, "Permit even this." And He touched his ear and healed him (Luke 22:50-51).

What was Malchus doing there in the first place?
He was probably holding one of the "lanterns, torches" (John 18:3) for his boss/owner, the high priest, who is one of the "chief priests" whom Jesus then chastises: Then Jesus said to the chief priests, captains of the temple, and the elders who had come to Him, “Have you come out, as against a robber, with swords and clubs? When I was with you daily in the temple, you did not try to seize Me. But this is your hour, and the power of darkness” (Luke 22:52-53).

So in front of whom did Jesus perform His last healing miracle?
The "high priest" (John 18:10), and right next to a torch or a lantern so that he can see it clearly.

What happened next?
See below.

But who had dispatched Judas to fetch the troops who will arrest Him?
It was Jesus (see One of you will betray Me).

Who "went forward" (John 18:4) and identified Himself when they arrived?
It was Jesus (see Jesus of Nazareth).

Who had the power to kill everyone who came but did not use it, and instead "permit" (Luke 22:51) Himself to be arrested?
It was Jesus (see above).

So, who directed and controlled the arrest of Jesus?