The fourth Oni mask ends up on Captain Black, resulting in Section 13 getting some new unwanted agents.
This episode provides examples of:
- All According to Plan: After Captain Black summons the Sumo Khan that defeat Hak Foo and apprehend the Enforcers, Tarakudo calmly remarks everything's going according to his plan before he makes his exit, with no one yet aware that he's allowing his henchmen to be Captured on Purpose.Tarakudo: Ahh, things are going exactly as I envisioned.
Finn: This is the plan?! - Batman Gambit: At the start of his Captured on Purpose plan, Tarakudo restrains Captain Black with iron bars and lifts him into the air. He does this so that Black will be forced to call in reinforcements, which the mask will interpret as summoning the Shadowkhan. Once it does so, the evil starts corrupting Black.
- Big "NO!": Jackie when Oni Black is about to hand over the masks to the three Enforcers.
- Bridge Logic: The totem pole which the Oni Mask is embedded on falls and is stuck between the opposite walls of a ravine.
- The Cameo: One of the people the Shadowkhan lock up in Section 13 is a Buttercup scout.
- Captured on Purpose: Tarakudo intentionally allows the Enforcers to be taken captive by Captain Black's Shadowkhan because Black's inevitable corruption under the Oni Mask's influence leads to him offering the Enforcers the three other masks stored at Section 13.
- The Corrupter: The oni mask does this to Captain Black by “talking” to him, convincing him to lock away innocent people because they’re not “one of us”.
- Curb-Stomp Battle: After getting the Oni Mask on his face, Captain Black easily beats up Hak Foo.
- Dark Is Not Evil: Merely wearing the Oni Mask doesn't turn Captain Black evil. Things change after he summons the Shadowkhan.
- Dragged by the Collar: The Sumo Khan do this to the Enforcers when capturing them.
- Enemy Without: Thanks to Jade using the Tiger Talisman, Captain Black's good half was separated from his mask-wearing dark side. The Yang half declares that it feels like "a burden's been lifted".
- Explain, Explain... Oh, Crap!: When Jackie wonders what Black will do under the mask's influence next, Jade comments that as long as they keep him in Section 13, what's the worst he could do...before they both remember that the other three Oni masks are in the vault.
- Fallen Hero: Captain Black turns into this once he summons the Shadowkhan.
- Finger Poke of Doom: One Sumo Khan sends Hak Foo flying through a wall with just a flip.
- Help, I'm Stuck!: When Uncle and Tohru take the phone booth entrance into Section 13, they end up getting stuck due to Tohru's girth. After Captain Black is back to normal, Uncle says there's one more thing to do: finding a phone-booth removal potion.
- I Warned You: Uncle, upon getting back to the Shadowkhan-infested Section 13.Uncle: Jackie! I told you! Do not allow Captain Black to summon Shadowkhan!
- Impact Silhouette: Hak Foo makes one as a Sumo Khan sends him flying through a wall.
- Incorruptible Pure Pureness: Unlike others who wore the masks, Captain Black is not corrupted the second he's wearing one. He at most simply enjoys how it enhances his already impressive physical skills, but he otherwise acts like his old self. Uncle reasons his inherent goodness is keeping the mask's effects at bay. It takes Tarakudo tricking him into summoning the Shadowkhan for it to kick in.
- Literal Split Personality: Jade uses the Tiger Talisman to free Captain Black's good side from the mask.
- Mighty Glacier: Captain Black's sumo Shadowkhan are physically strong and very durable, but they're also slow due to their size.
- Mundane Utility: Double-subverted. Captain Black replaces all the Section 13 agents with the Sumo Khan, claiming them to be better than humans in every way. We see several shots of the Sumo Khan typing on computers, checking folders, arresting people... and mopping the floor.
- "Oh, Crap!" Smile: Jackie and Jade do this when Captain Black informs them that the mask he’s wearing is talking to him, telling him who is friend and foe.
- Race Against the Clock: Though Uncle believes Black's willpower is keeping the mask under control, he knows it's only a temporary solution. He gets to work on a removal spell with Tohru and explicitly tells Jackie to keep Black from summoning any Shadowkhan. By the end of the episode, Uncle sees how things have spiraled out of control while he was gone.
- Rock–Paper–Scissors: Finn, Ratso and Chow have this contest to decide which one of them will go to fetch the mask from the totem pole sticking over a ravine. Ratso wins with one paper against two rocks, but since he doesn't remember that paper covers rock, Finn and Chow convince him that rock crushes paper. It's not before he's halfway across the pole that he figures out the bluff.
- Shout-Out: Jade calls the Oni Masks facehuggers at one point.
- Super-Strength: The Sumo Khan are so strong that one is able to send Hak Foo flying through a wall just by flicking its finger. Captain Black's good half needs the Ox Talisman to stand a chance against them.
- Super-Toughness: The Sumo Khan are so resilient that Hak Foo hurts his hand while striking one of them with all his might, and even Captain Black's good half can't disperse them just like that with the Ox Talisman.
- That Man Is Dead: When Jade cries out that the Captain Black she knows would never give the Oni Masks to the Enforcers, he responds that the Captain Black she knows is on permanent vacation. She proves him wrong by using the Tiger Talisman to separate Black's goodness from his mask-wearing dark side.Jade: Well, he's about to catch the next flight back!
- Title Drop: When Captain Black decides to embark on a rescue mission alone, he dismisses Jackie's concerns by saying that "ol' Black magic" is up for it.
- With Us or Against Us: Captain Black adopts this mindset under the Oni Mask's influence, first arresting people for not being on his and the mask's side, and then turning on Jackie and Jade when he overhears them planning to remove the Oni Masks stored in the vault.
- Your Mom: When one of the people imprisoned in Section 13's cells tries to appeal to his innocence, Chow tells him to save the drama for his mother.
