the mighty ill > (Death, decay; ill = evil)

4 Which, as a victor proud, gan ransack fast

gan > did

5 His inward parts, and all his entrails waste,

entrails > bowels, inner parts waste > (Vb.)

6 That neither blood in face, nor life in heart

That > [So that]

7 It left, but both did quite dry up, and blast;

blast > wither

8 As piercing levin, which the inner part