Looking at the diagram, both defensive ends (E) align in a “4i” (inside shoulder of the tackle) and play the B-gap with the nose tackle (N) working to the “front side of flow” (or the A-gap).

In the 4-3, the Will ‘backer is going to pursue to the football, shoot backside gaps and clean up on cutback runs. He is the “playmaker” at the second level for defenses that run the 40 front.