The ability to enter a state of self-induced tranquility. Not to be confused with Apathy. Opposite to Feral Mind.
Nerves of Steel
Soul of Ice (Ranma 1/2)
User can remain calm in virtually any situation, allowing them to think with perfect clarity even when under extreme emotional or physical distress. Users can endure mental stress, and can be essentially immune to emotional manipulation and highly resistant to torture.
Sosuke Aizen (Bleach) is completely calm and composed even in the midst of intense battle.
Zommari Rureaux (Bleach) meditates to keep calm and possibly being arrogant due to being the fastest Espada.
Shūkurō Tsukishima (Bleach) maintains his composed nature, even when overwhelmed and injured in battle.
When using Ultra Instinct, Goku (Dragon Ball Super) gains a clear and tranquil mind, giving him automatic and instantaneous reaction to any threat with the most suitable and seamless means to defend and attack.
Meliodas (Nanatsu no Taizai/The Seven Deadly Sins) Just before regaining his original power, he gained full control over his furious wrath.
As a mercenary ninja, Zabuza Momochi (Naruto) had attempted to suppress all emotions, and would stop at nothing to fulfill his mission.
Dracule "Hawk-Eye" Mihawk (One Piece) is one of the most serious characters in the world of One Piece and never unnecessarily reveals emotions on the battlefield.
Nico Robin (One Piece) is the extremely level headed member of the Straw Hats, who always makes cool (and always creepily scary) statements.
Donquixote Doflamingo (One Piece) is one of the most carefree characters in the world of One Piece never losing his signature smirk.
Van Augur (One Piece) is extremely calm and analytical even during battle.
Basil Hawkins (One Piece) portrays himself in a noble and enigmatic manner who remains completely calm regardless of situations.
Trafalgar Water D. Law (One Piece) is extremely laid-back guy who is nearly always seen calmly smiling.
Admiral Borsalino/Kizaru (One Piece) is a calm, very laid-back and easygoing fellow despite being one of the most powerful fighters in the Navy.
Charlotte Katakuri (One Piece) can remain calm even during extreme battles which allows him to control his Mochi Mochi no Mi making it look like Logia when it's Paramecia thanks to his Precognition.
Shun Sui Ju (Kingdom) is always seen with a calm expression, making him a dangerous opponent to read in both battle and combat.
Karasu (Yu Yu Hakusho) is calm and collected.
Kurama (Yu Yu Hakusho) is calm, calculating, cunning and analytical.
Shinobu Sensui (YuYu Hakusho)
Younger Toguro (Yu Y/u Hakusho) displays a calm and relaxed attitude.
Clear Note (Zatch Bell!) is able to do sadistic and evil actions in a remarkably calm manner.