Yank and Doodle [Yank [Dick Walters] (introduction, origin); Doodle [Rick Walters] (introduction, origin); Walt Walters (introduction, their father, the future Black Owl II); Von Goohn (villain, introduction)
Green Lama [Jethro Dumont]; Baroness Von Elsa (first appearance; villain); Hugo (first appearance; villain); the Imp (first appearance); Dr. Meruc (first appearance)