Recap: Batman The Animated Series The Underdwellers
- Absurdly-Spacious Sewer
- Abusive Parents: The Sewer King sees himself as a good parent to his "beloved children", even though he orders them to steal for him, punishes them severely for talking, and makes them live in deplorable conditions.
- Adult Fear: Batman is logically angry when Frog picks up and plays with a decorative gun on the wall of Wayne Manor, since it could have been loaded.
- Evil Cannot Comprehend Good: The Sewer King couldn't understand why Batman would bother saving his life.
- The Fagin: The Sewer King is the evil version
- First Time in the Sun: In the end, the Sewer King's captured orphans are brought into the sunlight at last.
- King of the Homeless: The Sewer King.
- Light Is Not Good: The Sewer King punishes a child for breaking his rule against "talking" (he cried out after injuring himself) by locking him in a room filled with bright lights for several hours.
- Averted at the end when the orphans enter the daylight again.
- Monster of the Week: The Sewer King.
- Papa Wolf: Batman was enraged by Sewer King's crimes against the orphans.
- Reckless Gun Usage: While being chased by Alfred in the Wayne mansion, Frog finds a collection of antique firearms. He grabs a blunderbuss off the wall and waves it around like a toy. Alfred immediately backs off, but Batman jumps in and grabs the gun out of the boy's hands. Batman notes, "It's not loaded, but it could have been."
- Save the Villain: Given the nature of the villain's crime, Batman seriously thought about averting the trope this time but it was eventually played straight.
- Suddenly Voiced: Frog gets a line at the end of the episode.
- The Voiceless: The Sewer King, believing that children should be seen and not heard, forces his charges to be silent at all times...or else.
- Thou Shalt Not Kill: Batman still goes by this, but he let the Sewer King know that we was very tempted to break it this time.