| Issue | V1#12 [12] |
| Published | July 1941 |
| Cover Price | 0.10 USD |
| Editing | John Reece? |
| Pencils | Jack Binder |
| Inks | Jack Binder |
| Characters | The Black Owl [Doug Danville]; The Reaper (first appearance; villain) |
| Script | Otto Binder |
| Pencils | Jack Binder |
| Inks | Jack Binder |
| Characters | Dr. Frost |
| Pencils | Ben Thompson |
| Inks | Ben Thompson |
| Pencils | Maurice Gutwirth |
| Inks | Maurice Gutwirth |
| Characters | Frankenstein; Bulldog [Denny Dunsan]; Victor Frankenstein; |
| Script | Dick Briefer |
| Pencils | Dick Briefer |
| Inks | Dick Briefer |
| Notes | References to HUNCHBACK OF NOTRE DAME, which Briefer adapted for JUMBO COMICS |
| Characters | Green Lama [Jethro Dumont]; Sing Po (first appearance; villain) |
| Script | Ken Crossen |
| Pencils | Charles Sultan |
| Inks | Charles Sultan |
| Characters | Voodini (last appearance); Whizzo (first appearance; villain) |
| Pencils | Jon Smalle |
| Inks | Jon Smalle |
| Letters | typeset |
| Characters | Twist Turner |
| Script | Four Roth Bros. (they wax Jennings for awhile) |
| Pencils | Four Roth Brothers [Irving Roir; Al Ross; Ben Roth; Salo Roth] |
| Inks | Four Roth Brothers |
| Characters | Power Nelson; Hertz (first appearance; villain) |
| Pencils | Paul Norris |
| Inks | Paul Norris |