drunk = devour. Figure of speech Prosopopoeia.App-6.
From the beginning = from [the flesh] of the chief leader of. Note the alternation: "I will make Mine arrows drunk with blood, And My sword shall devour much flesh; With the blood of the slain and of the captives, With [the flesh] of the chief leader of the enemy. "Compare Rev_19:17-21, to which this refers. See also Eze_39:17-20.