NET
12 When the army is taken away, the king of the south will become arrogant. He will be responsible for the death of thousands and thousands of people, but he will not continue to prevail.
Darby
12 And when the multitude shall have been taken away, his heart shall be exalted; and he shall cast down myriads; but he shall not prevail.
KJV
12 [And] when he hath taken away the multitude, his heart shall be lifted up; and he shall cast down [many] ten thousands: but he shall not be strengthened [by it].