Wong Chu wrote:
The Headmen appear in Defenders #21, a couple months after WWT #7.


  

I thought they didn't show up until #31? Here's how I see the next few Defenders volumes breaking down:

#3: Defenders #'s 17-20, G-S Defenders #'s 2-4, Marvel Team-Up #27, Marvel Two-In-One #'s 6-7
#4: Defenders #'s 21-30, G-S Defenders #5
#5: Defenders #'s 31-39, WWT #7