According to an interview with Valiantfans.com, Jim Shooter says he penciled the original promo piece which became the cover to Harbinger #1. David Lapham came in and touched-up the faces to match how he was drawing them in the book and added Kris, who wasn't in the original promo. He also says the cover was colored by Janet Jackson, but the explosion was actually painted by her.
Comic strip insert and coupon. The complete set of coupons (#1-6) was redeemable for a copy of Harbinger #0.