Adam Clarke on Daniel 11:20

Then shall stand up in his estate a raiser of taxes - Seleucus Philopater succeeded his father Antiochus. He sent his treasurer Heliodorus to seize the money deposited in the temple of Jerusalem, which is here called the glory of the kingdom, see 2 Maccabees 9:23. He was so cramped to pay the annual tax to the Romans, that he was obliged to burden his subjects with continual taxes.

He shall be destroyed, neither in anger - fighting against an enemy, nor in battle - at the head of his troops; but basely and treacherously, by the hand of Heliodorus his treasurer, who hoped to reign in his stead.