Kuroko (黒子, Kuroko), was used as an official who officiated the match in early Samurai Shodown games. He starts to challenge players as a hidden boss in Samurai Shodown II and continues to do so in other games of the series. Kuroko is an alias; his real name is shown in the credits of the second game; but it, keeping with the kuroko theme, is blurred with mosaics. His "real" name is revealed to English fans nearly a decade later as Dueling Judge: "Slick" Sukihiro. On his card in the English version of Card Fighters Clash he is called "The Ump".
Although he appears as his own character in the series, real life kuroko are meant to be anonymous and "invisible" stage men in Japanese theater. The color black (kuro) in Kabuki and Noh theaters, means to be invisible.
Similar characters appear in the Power Instinct series, though they have no relation to Slick, aside from a common occupation.
Not much is known about him or from where he comes from. He was forced to judge matches as a servant of Amakusa in Samurai Shodown because his other brothers were held hostage. After Amakusa's defeat, he reunites with his family. One of the brothers had a previous working relationship with Nicotine Caffeine and is well versed in necromancy.
He is an enigma. It's hard to tell which brother is under the Kuroko alias at what time. He may not even be human.
- Mimicry - Kuroko is notorious for parodying special moves of SNK characters from series such as Art of Fighting or King of Fighters. He can also morph into a copy of his opponents.
- Pump Up - Kuroko can temporarily project a topless and muscular version of himself to hurt his opponents. He has a distinct Big dipper scar on his chest.
- Flag Fighting - Kuroko's makes use of his flags as weapons.
- Multiple Attacks - Kuroko can kick his opponents a lot of times.
He dons a red flag and a white flag (used in martial arts competitions to denote when a player hits an opponent) as his weapons, and these cannot be destroyed or lost in battle. His stance is identical to that of Tung Fu Rue's from the Fatal Fury series (Special onward) and the King of Fighters series in Samurai Shodown II and Samurai Shodown VI.
- In hand-held version of Samurai Shodown (the only game where uses his own moves and can be disarmed) he uses boomerang flag toss and "backstage" teleport.
- In Samurai Shodown II, Kuroko parodies moves from other SNK characters, mainly from those in Fatal Fury or Art of Fighting (particularly sporting an array of projectiles lined into discipline called Kuroko's Eight Ultimate Projectiles (黒子八極弾, kuroko hakkyoku dan). Unlike every other character in the game, it was his outfit that became red as his rage bar filled up. He also can't be thrown normally, like Earthquake.
- He morphs into his opponent in Samurai Shodown III, and can be only used by CPU.
- In Samurai Shodown 64 he abandons his flags and relies on close-ranged martial arts (parodying the attacks of rest of game's cast) and grappling (parodying Hanzo and Hanma Yagyu) to fight, with his special discipline now being called Kuroko's Eight Ultimate Fists (黒子八極拳, kuroko hakkyoku ken) and consisting from combos.
- He morphs into random character in Samurai Shodown! 2, and can only be "used" by player, being essentially a random select icon.
- In Samurai Shodown VI, he uses flags again, and his special moves further parody King of Fighters characters. Kuroko's Eight Ultimate Projectiles (黒子八極弾, kuroko hakkyoku dan) discipline returns, being also King of Fighters-themed and having unlockable 9th "projectile number zero" (Terry's Triple Geyser).
He is deemed as extremely powerful character in all of his playable incarnations (aside of hand-held), and therefore is banned from competitive play.
- お調子六句, Ochoushi Rokku (The Tune of Six Sentences) - Samurai Shodown II. The name of the theme is a pun, since it sounds as "Freestyle Rock" in Japanese.
- 舞闘劇, Butougeki (Dance of Battle) - Samurai Shodown III
- True Garage Spirits (Spiritual Black Men Mix) - Samurai Remix VA
- Masaki Usui - Samurai Shodown and III
- Eiji Yano - Samurai Shodown II (while judging)
- Toshikazu Nishimura - Samurai Shodown II (during battle)
- Kaori Minami - Samurai Shodown 64
- Takumi Satō - Samurai Shodown VI
- Samurai Shodown - judge; playable character in handheld version only
- Samurai Shodown II - judge and challenger; hidden character playable in the console version only
- Samurai Shodown III - challenger
- Samurai Shodown IV - cameo in Gaira's ending
- Shinsetsu Samurai Spirits: Bushidou Retsuden - save point
- Samurai Shodown 64 - hidden character (also gameplay instructor & post-ending cameo)
- Samurai Shodown! 2 - random select icon
- Samurai Shodown V Special - "judge" (actually part of one of backgrounds)
- Samurai Shodown VI - judge and challenger; hidden character playable in the console version only
- Samurai Shodown (2019) - "judge" (actually part of one of backgrounds)
- Days of Memories (third title) - in-text cameo; appears in various story modes
- Grandblue Fantasy - Boss character
- Kimi wa Hero
- Samurai Shodown: Oborozuki Densetsu
- Samurai Shodown IV - in Gaira's ending
- Maid by Iroha
- Samurai Spirits (pachinko)
- Samurai Spirits Gaiden: Cham Cham
- Samurai Spirits ~Kengou Hachiban Shoubu~
- When asked "The path of the sword is?", Kuroko's response is "An opportunity to witness a great match."