Tales to Astonish (vol. 1) #59 (Sep. 1964):
“Enter: The Hulk”
by Stan Lee, Dick Ayers, Paul Reinman
11 characters in this story:
With issue #59, the Tales to Astonish comic book series had long featured Hank Pym (a.k.a. "Ant-Man" and then "Giant-Man") as the series star and featured cover character. This had been the case since Tales to Astonish #35. In issue #59, the cover story prominently features the Hulk as a co-star in Giant-Man's feature story. This is a "warm-up" for the next issue, #60, in which the series begins featuring the Hulk as the series co-star.
Tales to Astonish continued to be split between features starring the Hulk and Giant-Man (with logos for both heroes emblazoned prominently on the cover), from issue #60 through #60. Beginning with issue #61, the co-features in Tales to Astonish switched from the Hulk and Giant-Man to the Hulk and Sub-Mariner. The series continued that way for over 40 issues, until issue #101. Then the series title switched to The Incredible Hulk, continuing the numbering of the Tales to Astonish series with #102.