The "Detective Comics" logo and the "POW!" "KRAK!" and "WHAPP!" were intended as clues that you should look at 'Tec issues around the time of the Batman show (1966-68)
1. The Monarch of Menace. He only appeared in Detective #350 during the Silver Age, although he did come back for an encore in 1981.
2. Dr Tzin-Tzin. Obviously a Fu Manchu knockoff, Dr Tzin-Tzin made his lone SA appearance in Detective #354. He returned several times in the 1970s.
3. The Outsider (aka Alfred). He was a shadowy figure in the background of several stories in the mid-1960s and finally appeared (and disappeared) in Detective #356.
4. Mr Esper first popped up in Detective #352's Batman's Crime Hunt A-Go-Go. He found a way to broadcast messages to Batman telling him where a crime was about to take place (so that he could commit a crime where Batman had been). Mr Esper returned in Batman Batman #201 and #209 and later became a Teen Titans villain rechristened as Captain Calamity.
5. This was the trick question, because the boy in the panel is Mark Desmond, who later becomes the Blockbuster after a growth serum makes him big and berserk.
Kudos to Robert McKinney who got all five correct and to Michael Sensei and Michael Rebain who each got three answers.
