The user can go into a mode or form made for stealth, which allows for the user to slip past foes and get in and out of areas undetected. Enemies will be unable to detect the user, and the user is also able to be unnoticed in public, and not be tracked easily.
Miho Jufuku (A Certain Scientific Railgun) using her Dummy Check to cause her known existence to be invisible to those in front of her, allowing her to launch stealthy attacks.
Akame (Akame Ga Kill!) hiding her killing intent completely, moving at mach speed, enabling her to slay her opponents stealthily.
Train Heartnet (Black Cat) can easily use his immense speed to rush through a busy party room and knock down all guards to assassinate his target at pointblank range, and leave before anyone notices he was there.
Shinobu Negero (Buso Renkin) using his Secret Trail to hide inside his alternate dimension, throwing his sword at unsuspecting angles for stealthy attacks.
Zabuza Momochi (Naruto) using his Hiding in Mist Technique in conjuncture with his signature Silent Killing, entering stealth mode so powerful, the opponent won't know what happened until it's too late.
Donqixote Rosinante (One Piece) using the powers of his Nagi Nagi no Mi to prevent sound from leaking into or out of his field, allowing him to launch silent attacks disregarding the loudness it would normally cause.
Primarch Corvus Corax (Warhammer 40k) is an exceptional stealthy warrior that can hide from his enemies even in the direct line of sight.