Kenner Canada produced two 12-Back card styles for the twelve 1st series action figures. The carded Batman shown above illustrates one of the two styles: the "Free Poster Offer" variety. The "Free Figure Offer" (Steppenwolf) represents the other Kenner Canada 1st series card style. While Kenner required submission of only two proof-of-purchase seals for free poster redemption by December 31, 1984, Kenner Canada required submission of three proof-of-purchase seals by March 31, 1985.
To date I've been able to document 10 of the 12 first series characters in this packaging style. It's quite possible all twelve were released, so research and documentation is still considered ongoing. Batman is extremely rare in carded form on the Kenner Canada 12-Back "Free Poster Offer" card style. Based on my collecting experiences, I classify it as the single rarest card style for Batman out of all Kenner and Kenner Canada packaging types.