The user can utilize secret arts, specialized techniques or practices that only a select few know how to/can use. Reasons may vary, from being dangerous to others or themselves, to only being available to that worthy of them.
The Shredder (Batman vs. Teenage Mutant Ninja Turtles) is one of only two living ninja masters that know the powerful but dangerous Sato-oshi strike...
...with the other being Splinter.
Lady Shiva (DC Comics) knows several martial arts skills that no one else knows, such as her signature Leopard's Blow, due to her killing the last master of the practice.
The Yardrat (Dragon Ball series) are a weak species in terms of raw power but has access to a rather secret technique of
Ki manipulation technique known as
Spirit Control. Training in this brings about balance between body and spirit...
...Vegeta being fully trained in the art to combat Planet-Eater Moro...
...and Goku Black learning the technique after stealing Son Goku's body...
Souichirou Kuzuki (Fate/stay night) is a master of a secret assassination art simply known as Snake.
Roy Mustang (Fullmetal Alchemist) is the only known user of flame alchemy...
...with the only known knowledge of the art being a tattoo on Riza Hawkeye's back.
The Ripple/Hamon (JoJo's Bizarre Adventure) is known only to a small percentage of humanity, with even fewer being capable of learning it.
The Bride (Kill Bill) is the only person in the world besides Pai Mei, the creator, to know the Five Point Palm Exploding Heart Technique.
Fenghuang (Kung Fu Panda) mastered all seven of the Seven Impossible Moves. She later mastered and demonstrated five additional impossible moves that not even Shifu knew existed, bringing a total of the Twelve Impossible Moves.
Po (Kung Fu Panda) learned two of the original Seven Impossible Moves, the Thundering Wind Hammer and the Mongolian Fireball with just one look. He also learned how to counter the Wind Hammer technique.
Link (The Legend of Zelda series) regularly learns a variety of secret sword techniques, most notably the advanced strikes and moves of the Hero's Shade/Hero of Time...
...and the Spin Attack, taught to him by his uncle and passed down their family.
Shikamaru Nara's (Naruto) Shadow Possession Jutsu is one of many examples of a hiden, secret techniques passed down from generation to generation in certain regions, families, and clans.
The Mangekyō Sharingan (Naruto)
The Izanagi technique (Naruto), a forbidden Jutsu that allows the user to control their state of existence, escaping unfavorable outcomes and rewriting the results.
Rob Lucci (One Piece) using Sai Dai Rin: Rokuogan, the secret seventh technique of Six Powers/Rokushiki only available to those who have absolute mastery of the other six skills.
Unlike the other two forms of Haki, Conqueror's/Haoshoku Haki (One Piece) can only be used and harnessed by one in several million people.
Due to its tremendous power and speed, the Hiten Mitsurugi-ryū style of kenjutsu (Rurouni Kenshin) is strictly taught to a select few, a single master training a single apprentice exclusively.
Ashford (Slayers) is among the few who knows the secret culinary art of Dragon Cuisine.
Lord Voldemort (Harry Potter) is the creator of Unsupported Flight, a rare and thought-to-be impossible spell that enables a witch or wizard to fly without the aid of a broomstick...
...teaching Severus Snape to do so, the two being the only known wizards capable of it prior to their deaths.
Cheon Yeo Woon (Nano Machine) rediscovered and mastered the true form of the Heavenly Demonic Sword Art martial art that was lost for centuries with the aid of his Nano machine.
Implied to be the only living mortal who knows it, Roy Greenhilt (The Order of the Stick) uses the Spellsplinter Maneuver, a fighting technique that allows one to interrupt a caster's spell, even if the caster is casting defensively.
Miyamoto Usagi (Usagi Yojimbo) is the only mortal to have master and use Tengu Style Swordsmanship, the secret kenjutsu of the
Tengu.
Hokuto No Ken - North Star Humanist Face Breaking Fist
Toki opens the road for Kenshiro
Raoh, Toki is waiting... (Remastered - Kareta Daichi)-2
-HD- Jojo - Joseph Joestar VS Police-2
Joseph Joestar vs ACDC (part 1)-2
JJBA Joseph defeats Esidisi-2
ジョジョ- Caesar vs. Wamuu (1) 『HD』-2
ジョジョ- Caesar vs. Wamuu (2) 『HD』-2
ジョジョ- Caesar's Final Hamon 『HD』
Jojo's Bizarre Adventure - Wired Beck-2
JoJo and Stroheim's Bizarre Adventure-2
JJBA Stardust Crusaders - Joseph Joestar Vs Dio- Battle of Wits-2
Kakashi's mangekyo sharingan
Kill Bill Vol. 2 (2004) - The Five Point Palm Exploding Heart Technique Scene (12 12) Movieclips
Batman vs Shredder - Batman vs Teenage Mutant Ninja Turtles-2